TLS und SMTP - Strotmann.de

Transcription

DNSSEC und Dane
TLS Transportverschlüsselung mit DNSSEC Unterstützung
Jörg Zimmermann, Patrick Kötter, Carsten Strotmann
© Men & Mice http://menandmice.com Thursday 30 October 14
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Thursday 30 October 14
TLS und SMTP
4
TLS und SMTP
4
TLS und SMTP
4
TLS und SMTP
4
TLS und SMTP
5
TLS und SMTP
5
TLS und SMTP
5
TLS und SMTP
STARTTLS?
5
TLS und SMTP
STARTTLS?
6
TLS und SMTP
STARTTLS!
6
STARTTLS?
TLS und SMTP
STARTTLS!
6
STARTTLS?
TLS und SMTP
STARTTLS!
6
STARTTLS?
TLS und SMTP
STARTTLS!
6
STARTTLS?
TLS und SMTP
Fälschung
7
TLS und SMTP
Fälschung
7
TLS und SMTP
STARTTLS?
Fälschung
7
TLS und SMTP
STARTTLS?
Fälschung
7
TLS und SMTP
STARTTLS?
STARTTLS!
Fälschung
7
TLS und SMTP
STARTTLS?
STARTTLS!
Fälschung
7
TLS und SMTP
STARTTLS?
STARTTLS!
Fälschung
7
TLS und SMTP
Men in the
Middle
8
TLS und SMTP
Men in the
Middle
8
TLS und SMTP
STARTTLS?
Men in the
Middle
8
TLS und SMTP
STARTTLS?
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS?
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS?
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS?
STARTTLS!
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS?
STARTTLS!
STARTTLS!
Men in the
Middle
8
TLS und SMTP
STARTTLS?
STARTTLS?
STARTTLS!
STARTTLS!
Men in the
Middle
8
TLS und SMTP
Men in the
Middle
9
TLS und SMTP
Men in the
Middle
9
TLS und SMTP
STARTTLS?
Men in the
Middle
9
TLS und SMTP
STARTTLS?
NEIN!
Men in the
Middle
9
TLS und SMTP
STARTTLS?
NEIN!
Men in the
Middle
9
TLS und SMTP
STARTTLS?
STARTTLS?
NEIN!
Men in the
Middle
9
TLS und SMTP
STARTTLS?
NEIN!
STARTTLS?
NEIN!
Men in the
Middle
9
TLS und SMTP
STARTTLS?
NEIN!
STARTTLS?
NEIN!
Men in the
Middle
9
TLS und SMTP
STARTTLS?
NEIN!
STARTTLS?
NEIN!
Men in the
Middle
9
TLS != PGP
TLS
10
TLS != PGP
TLS
PGP
10
TLSA/SMTP
•
Absicherung von TLS Zertifikaten über DNS(SEC)
•
Hash des Zertifikates (oder das ganze Zertifikat) werden im DNS
gespeichert
•
Annahme: der Besitzer der DNS-Domain ist auch Besitzer des
Zertifikates
11
TLSA/SMTP
•
Sicherheitslevel ist vergleichbar mit Domain-(E-Mail) validierten
Zertifikaten
•
TLSA kann self-signed Zertifikate absichern
•
TLSA kann X509 Zertifikate von Certification Authorities (Symantec,
Comodo, StartSSL, CACert …) absichern
12
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
TLS Zertifikat
13
SMTP
MTA
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
TLS Zertifikat
13
SMTP
MTA
TLS und SMTP
DNS
DNS
TLSA?
STARTTLS?
STARTTLS!
SMTP
MTA
TLS Zertifikat
13
SMTP
MTA
TLS und SMTP
DNS
DNS
TLSA?
STARTTLS?
STARTTLS!
SMTP
MTA
TLS Zertifikat
13
SMTP
MTA
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
14
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
14
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
SMTP
MTA
14
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
14
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
14
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
TLS Zertifikat
14
SMTP
MTA
TLS und SMTP
DNS
DNS
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
15
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
15
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
15
DNSSEC
check
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
STARTTLS!
SMTP
MTA
SMTP
MTA
15
DNSSEC
check
TLS und SMTP
DNS
DNS
STARTTLS!
STARTTLS!
SMTP
MTA
SMTP
MTA
16
TLS und SMTP
DNS
DNS
STARTTLS!
STARTTLS!
SMTP
MTA
SMTP
MTA
16
TLS und SMTP
DNS
DNS
STARTTLS!
STARTTLS!
SMTP
MTA
SMTP
MTA
16
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
Men in the
Middle
17
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
Men in the
Middle
17
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
Men in the
Middle
17
SMTP
MTA
TLS und SMTP
DNS
DNS
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
17
SMTP
MTA
TLS und SMTP
DNS
DNS
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
17
SMTP
MTA
TLS und SMTP
DNS
DNS
TLSA?
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
17
SMTP
MTA
TLS und SMTP
DNS
DNS
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
18
SMTP
MTA
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
18
SMTP
MTA
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
18
SMTP
MTA
DNSSEC
check
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
18
SMTP
MTA
DNSSEC
check
TLS und SMTP
DNSSEC
check
DNS
DNS
TLSA!
STARTTLS?
NEIN!
SMTP
MTA
Men in the
Middle
18
SMTP
MTA
ALARM!
MITM Angriff
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
Fälschung
TLS und SMTP
DNS
DNS
SMTP
MTA
SMTP
MTA
Fälschung
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
SMTP
MTA
Fälschung
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
TLS und SMTP
DNS
DNS
TLSA?
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
TLS und SMTP
DNS
DNS
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
DNSSEC
check
TLS und SMTP
DNS
DNS
TLSA!
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
DNSSEC
check
TLS und SMTP
DNSSEC
check
DNS
DNS
TLSA!
STARTTLS?
SMTP
MTA
SMTP
MTA
STARTTLS!
Fälschung
ALARM!
Falscher
Server!
Infrastruktur DNS
•
DNSSEC Validierung (Caching DNS Resolver)
•
•
BIND 9, Unbound, dnsmasq, Windows 2012
DNSSEC signierte Zonen (Authoritativer DNS Server)
•
BIND 9, NSD, Knots, Y.A.D.I.F.A., PowerDNS, Bundy-DNS, Windows 2012*
21
* Windows 2012(R2) unterstützt derzeit nicht den TLSA Record Typ
Infrastruktur Mail
•
MTA mit TLSA Unterstützung
•
•
Postfix 2.11, Exim (in Vorbereitung)
TLS Zertifikate
•
EV-Zertifikat (Extended Validation)
•
DV-Zertifikat (Domain Validation)
•
Self-signed Zertifikat
22
BIND 9.9.x DNSSEC
•
DNSSEC Validierung einschalten:
options {
…
dnssec-validation auto;
dnssec-lookaside auto;
};
23
TLSA-Record
•
TLSA hash manuell erstellen:
$ openssl x509 -in mail.example.de.crt -outform DER | openssl sha256 (stdin)=
8cb0fc6c527506a053f4f14c8464bebbd6dede2738d11468dd953d7d6a3021f1
•
TLSA Record:
_25._tcp.mail.example.de.
3600 IN TLSA 3 0 1 (
8cb0fc6c527506a053f4f14c8464bebbd6dede
2738d11468dd953d7d6a3021f1 )
24
TLSA-Record
•
TLSA Record mit ldns-dane erstellen:
$ ldns-dane create www.bund.de 443
_443._tcp.www.bund.de. 3600IN TLSA3 0 1
8f28b062eaa9f917042a63d35d99e017c68d89eaa314c49a3ef94b6e770b0a49
•
TLSA Record mit ldns-dane prüfen:
$ ldns-dane verify www.bund.de 443
77.87.229.48 dane-validated successfully
25
TLSA-Record testen
shell> dig _25._tcp.mail.example.de. +dnssec +m
; <<>> DiG 9.9.5 <<>> _25._tcp.mail.example.de TLSA +dnssec +m
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13973
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 4096
;; QUESTION SECTION:
;_25._tcp.mail.example.de. IN TLSA
;; ANSWER SECTION:
;;
;;
;;
;;
3588 IN TLSA 3 1 1 (
2738d11468dd953d7d6a3021f1 )
3588 IN RRSIG TLSA 8 5 3600 (
20140324063111 20140317121843 4390 example.de.
RBgAAzQx3gks0KKJHuJ7qKd61jpY8E6dwDM6inPPa6Ee
xV8OBnAzhF4RMKSabHF0LNwRzWqE5xNfPibMQFDoDRKJ
/QiNgux/IXti3JqtH4BkT0w7Ooi+8DZsil9BTjg6WkaX
1FuJ4rJ2r3hXS7eIOFWtOF7pPVPdIIaRB6xp+1A= )
Query time: 9 msec
SERVER: 127.0.0.1#53(127.0.0.1)
WHEN: Mon Mar 17 19:29:45 CET 2014
MSG SIZE rcvd: 142
26
TLSA-Record testen
DNSSEC
check OK
; <<>> DiG 9.9.5 <<>> _25._tcp.mail.example.de
;;
;;
;;
;;
TLSA +dnssec +m
global options: +cmd
Got answer:
->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13973
flags: qr rd ra ad; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; ANSWER SECTION:
;;
;;
;;
;;
3588 IN TLSA 3 1 1 (
2738d11468dd953d7d6a3021f1 )
3588 IN RRSIG TLSA 8 5 3600 (
20140324063111 20140317121843 4390 example.de.
Query time: 9 msec
SERVER: 127.0.0.1#53(127.0.0.1)
WHEN: Mon Mar 17 19:29:45 CET 2014
MSG SIZE rcvd: 142
26
TLSA-Record testen
DNSSEC
check OK
;;
;;
;;
;;
TLSA +dnssec +m
Got answer:
TLSA
Record
;; ANSWER SECTION:
;;
;;
;;
;;
3588 IN TLSA 3 1 1 (
2738d11468dd953d7d6a3021f1 )
3588 IN RRSIG TLSA 8 5 3600 (
20140324063111 20140317121843 4390 example.de.
Query time: 9 msec
SERVER: 127.0.0.1#53(127.0.0.1)
WHEN: Mon Mar 17 19:29:45 CET 2014
MSG SIZE rcvd: 142
26
TLSA-Record testen
DNSSEC
check OK
;;
;;
;;
;;
TLSA +dnssec +m
Got answer:
TLSA
Record
;; ANSWER SECTION:
;;
;;
;;
;;
3588 IN TLSA 3 1 1 (
2738d11468dd953d7d6a3021f1 )
3588 IN RRSIG TLSA 8 5 3600 (
20140324063111 20140317121843 4390 example.de.
Query time: 9 msec
SERVER: 127.0.0.1#53(127.0.0.1)
WHEN: Mon Mar 17 19:29:45 CET 2014
MSG SIZE rcvd: 142
26
DNSSEC
Signatur
Postfix Konfiguration
•
TLSA Prüfung in der Postfix Konfiguration:
shell> postconf -e "smtpd_use_tls = yes"
shell> postconf -e "smtp_dns_support_level = dnssec"
shell> postconf -e "smtp_tls_security_level = dane"
27
STARTTLS testen
•
Test einer STARTTLS-Verbindung zum Mailserver:
shell> openssl s_client -connect mail1.example.de:25 -starttls smtp
CONNECTED(00000003)
--Certificate chain
0 s:/C=DE/ST=State/L=City/O=Company/OU=Mailserver/CN=mail1.example.de
i:/C=DE/ST=State/L=City/O=Company/OU=Mailserver/CN=mail1.example.de
--Server certificate
-----BEGIN CERTIFICATE----[..]
Start Time: 1394991261
Timeout
: 300 (sec)
Verify return code: 18 (self signed certificate)
--221 2.0.0 Bye
closed
shell>
28
Postfix log
(ungesichertes TLS)
•
Postfix log TLS ohne DNSSEC TLSA Prüfung (DANE):
Mar 16 19:10:55 m3 postfix/qmgr[25923]: 2B1A680337:
from=<[email protected]>, size=291, nrcpt=1 (queue active)
Mar 16 19:11:03 m3 postfix/smtp[25929]: Untrusted TLS connection established to
mail1.example.de[2001:db8:100::25]:25: TLSv1 with cipher ECDHE-RSA-AES256-SHA
(256/256 bits)
Mar 16 19:11:05 m3 postfix/smtp[25929]: 2B1A680337: to=<[email protected]>,
relay=mail1.example.de[2001:db8:100::25]:25, delay=16, delays=6.2/0.01/7.9/2.1,
dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 3fn80C2DP5zTT)
Mar 16 19:11:05 m3 postfix/qmgr[25923]: 2B1A680337: removed
29
Postfix log
(DNSSEC gesichertes TLS)
•
Postfix log TLS mit DNSSEC TLSA Prüfung (DANE):
Mar 16 19:20:01 m3 postfix/qmgr[26122]: 8FBEE80337:
from=<[email protected]>, size=285, nrcpt=1 (queue active)
Mar 16 19:20:01 m3 postfix/smtp[26131]: Verified TLS connection established to
mail.example.de[2001:db8:100::25]:25: TLSv1 with cipher ECDHE-RSA-AES256-SHA
(256/256 bits)
Mar 16 19:20:03 m3 postfix/smtp[26131]: 8FBEE80337: to=<[email protected]>,
relay=mail.example.de[2001:db8:100::25]:25, delay=149, delays=147/0.03/0.13/1.8,
dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 3fn8BY3ltPzTT)
Mar 16 19:20:03 m3 postfix/qmgr[26122]: 8FBEE80337: removed
30
posttls-finger
(DNSSEC gesichertes TLS)
•
Posttls-finger TLSA Prüfung (ab Postfix 2.11):
$ posttls-finger mail.bund.de
posttls-finger: using DANE RR: _25._tcp.mx2.bund.de IN TLSA 3 0 1 59:E3:CF:5F:A1:51:55:3F:45:76:C9:4C:
25:00:D7:05:EF:DD:D8:55:B6:A5:9D:88:D2:8D:03:28:87:6A:04:CB
posttls-finger: Connected to mx2.bund.de[77.87.228.110]:25
posttls-finger: < 220 mx2.bund.de ESMTP
posttls-finger: > EHLO m3.myinfrastructure.org
posttls-finger: < 250-bn4-node11.sc.bund.de
posttls-finger: < 250-PIPELINING
posttls-finger: < 250-SIZE 20961280
posttls-finger: < 250-ETRN
posttls-finger: < 250-STARTTLS
posttls-finger: < 250-ENHANCEDSTATUSCODES
posttls-finger: < 250 8BITMIME
posttls-finger: > STARTTLS
posttls-finger: < 220 2.0.0 Ready to start TLS
posttls-finger: mx2.bund.de[77.87.228.110]:25: depth=0 matched end entity certificate sha256 digest 59:E3:CF:5F:A1:51:55:3F:
45:76:C9:4C:25:00:D7:05:EF:DD:D8:55:B6:A5:9D:88:D2:8D:03:28:87:6A:04:CB
posttls-finger: mx2.bund.de[77.87.228.110]:25: Matched subjectAltName: mx2.bund.de
posttls-finger: mx2.bund.de[77.87.228.110]:25 CommonName mx2.bund.de
posttls-finger: mx2.bund.de[77.87.228.110]:25: subject_CN=mx2.bund.de, issuer_CN=CA IVBB Deutsche Telekom AG 11,
fingerprint=72:78:BE:C8:3E:61:A0:12:BE:BF:3B:79:F0:CE:9A:A2:8C:26:24:FF, pkey_fingerprint=3A:3E:5F:A4:50:F8:DD:FC:56:35:FF:
08:2A:F9:ED:82:B9:AB:7B:82
posttls-finger: Verified TLS connection established to mx2.bund.de[77.87.228.110]:25: TLSv1 with cipher DHE-RSA-AES256-SHA (256/256
bits)
posttls-finger: > EHLO m3.myinfrastructure.org
posttls-finger: < 250-bn4-node11.sc.bund.de
posttls-finger: < 250-PIPELINING
posttls-finger: < 250-SIZE 20961280
posttls-finger: < 250-ETRN
posttls-finger: < 250-ENHANCEDSTATUSCODES
posttls-finger: < 250 8BITMIME
posttls-finger: > QUIT
posttls-finger: < 221 2.0.0 Bye
31
TLSA-Info Webseite
http://tlsa.info
DANE TLSA Vorteile
•
Verschlüsselte Verbindung zwischen Server wird authentisiert
•
STARTTLS "downgrade" Angriffe werden verhindert
•
TLS/SSL Zertifikate sind gegen Fälschung abgesichert
•
CRL/OCSP wird nicht benötigt, um TLS/SSL Zertifikate auszutauschen
Mehr als nur SMTP
•
TLSA für HTTPS
•
OPENPGPKEY — PGP Schlüssel im DNS
•
IPSECKEY — IPSEC Schlüssel im DNS
•
SSHFP — SSH Server Fingerprints
•
Prosody Jabber Server
http://bridge.grumpy-troll.org/2014/05/xmpp-dane-with-prosody/
•
Gajim Jabber Client
https://github.com/irl/gajim
•
S/MIME
•
SRV — DNS Service Discovery
www.dnssec-validator.cz
www.dnssec-validator.cz
Internet “in der Box”
Authoritative DNS
“.”, “org”, “dnslab.org”
recursive DNS
.252
.251
192.168.53/24
student workstations
192.168.53.128-148 (DHCP)
10.0.0.0/24 (WLAN “dns-training”)
virtual servers
192.168.53.101, 102, 103 ...
DNS Sicherheitsprobleme
“Triggered” Cache Poisioning
Cache
ISP
resolving DNS Server
evil resolver
“alternic.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.alternic.net/A
Cache
ISP
evil resolver
“alternic.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
“alternic.net”
authoritative DNS
Server
Cache
ISP
Interative query for
www.alternic.net/A
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
Cache
ISP
www.alternic.net/A
response including bogus
www.internic.net/A RR
“alternic.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
Cache
ISP
www.alternic.net/A
“alternic.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
Cache
ISP
www.alternic.net/A
“alternic.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
ISP
www.alternic.net/A
“alternic.net”
authoritative DNS
Server
Cache
Recursive query for
www.internic.net/A
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
ISP
www.alternic.net/A
“alternic.net”
authoritative DNS
Server
Cache
Recursive query for
www.internic.net/A
unsuspecting
resolver
Recursive query for
www.alternic.net/A
evil resolver
ISP
www.alternic.net/A
“alternic.net”
authoritative DNS
Server
Cache
Recursive query for
www.internic.net/A
bogus
response
unsuspecting
resolver
Probleme mit den Zufallszahlen
• Die Query-IDs in DNS Anfragen sind nicht immer zufällig gewählt
Cache
ISP
evil resolver
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.mybank.net/A
Cache
ISP
evil resolver
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
Recursive query for
www.mybank.net/A
evil resolver
“mybank.net”
authoritative DNS
Server
Cache
ISP
www.mybank.net/A
unsuspecting
resolver
• Dies kann von Angreifern ausgenutzt werden
Cache
ISP
evil resolver
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
flood of responses for www.mybank.net with pre-calculated IDs
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
unsuspecting
resolver
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
Recursive query for
www.mybank.net/A
unsuspecting
resolver
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
Recursive query for
www.mybank.net/A
unsuspecting
resolver
Cache
ISP
evil resolver
response for
www.mybank.net/A RR
“mybank.net”
authoritative DNS
Server
Recursive query for
www.mybank.net/A
bogus
response
unsuspecting
resolver
Sommer 2008: Dan Kaminski
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
HTTP
request
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
HTTP
request
evil resolver
Webpage with thousands
of fake image links
<img
<img
<img
<img
....
Cache
src=”aaaaa.mybank.com”..
src=”aaaab.mybank.com”..
src=”aaaac.mybank.com”..
src=”aaaad.mybank.com”..
“mybank.com”
authoritative DNS
Servers
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
Each
Image Tag will trigger one DNS lookup
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
Each
unsuspecting
resolver
evil web-server
DNS lookups will be send to the authoritative DNS Servers
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
Each
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Attacker will swamp
caching DNS Server
with fake responses
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Attacker will swamp
caching DNS Server
with fake responses
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Attacker will swamp
caching DNS Server
with fake responses
Some good answers will loose the race
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Attacker will swamp
caching DNS Server
with fake responses
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Attacker will swamp
caching DNS Server
with fake responses
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
Fake response
will be cached
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
request for www.mybank.com./A RR
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
false answer from poisoned cache
unsuspecting
resolver
evil web-server
HTTP
request
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
Client is connecting to a “pharming” website
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
HTTP
request
unsuspecting
resolver
• Angreifer plazieren falsche Delegationsinformationen in einen DNS Cache
;; ANSWER SECTION:
aaaa.mybank.com.
120
IN
A
1.2.3.4
;; AUTHORITY SECTION:
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
;; ADDITIONAL SECTION:
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
;; ANSWER SECTION:
aaaa.mybank.com.
120
IN
A
1.2.3.4
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
hohe TTL
;; ANSWER SECTION:
aaaa.mybank.com.
120
IN
A
1.2.3.4
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
hohe TTL
falsche IP Adressen der DNS Server
DNS poisoning durch IP Fragmente
• Ein neuer Angriff, vorgestellt auf der IETF 87 in Berlin August 2013
• benötigt große DNS-Antwort-Pakete, welche auf dem Transportweg fragmentiert werden (z. B. große TXT-Record-Sets - SPF etc)
• dieser Angriff wirkt speziell bei DNSSEC signierten Zonen (große Antworten), wenn der DNS Resolver die Daten nicht validiert!
• DNSSEC Resolver validieren und antworten mit “SERVFAIL”, aber die Client-Maschine hat auch einen DNS-Server in der Konfiguration, welcher nicht DNSSEC validiert, und die gefälschte Antwort kommt durch
• laut Forschungen von Geoff Huston (APNIC) sind diese Situationen häufig
IP-Fragment-Angriff (1)
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
HTTP
request
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
HTTP
request
evil resolver
Webpage with that triggers DNS requests with large DNS answers
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
DNS lookup for the domain name
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
DNS lookups will be send to the authoritative DNS Servers
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
Answer with Fragment part 1
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
Attacker will swamp
caching DNS Server
with fake fragment 2 packets
evil resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
Attacker will swamp
caching DNS Server
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
Attacker will swamp
caching DNS Server
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
Attacker will swamp
caching DNS Server
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
Fake response
will be cached
unsuspecting
resolver
evil web-server
evil resolver
“mybank.com”
authoritative DNS
Servers
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
HTTP
request
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
unsuspecting
resolver
evil web-server
Client is connecting to a “pharming” website
“mybank.com”
authoritative DNS
Servers
evil resolver
Cache
HTTP
request
unsuspecting
resolver
IP-Fragment-Angriff
• Angreifer versuchen falsche Delegations-NS-Records in den Cache zu bringen
;; ANSWER SECTION:
mybank.com.
120
IN
SPF
"v=spf1, a: 192.0.2.10, 192.0.2.22 ..."
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
Fragment 1
Fragment 2
IP-Fragment-Angriff
;; ANSWER SECTION:
mybank.com.
120
IN
SPF
"v=spf1, a: 192.0.2.10, 192.0.2.22 ..."
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
grosse Antwort erzwingt Fragmentierung
Fragment 1
Fragment 2
IP-Fragment-Angriff
;; ANSWER SECTION:
mybank.com.
120
IN
SPF
"v=spf1, a: 192.0.2.10, 192.0.2.22 ..."
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
hohe TTL
Fragment 1
Fragment 2
IP-Fragment-Angriff
;; ANSWER SECTION:
mybank.com.
120
IN
SPF
"v=spf1, a: 192.0.2.10, 192.0.2.22 ..."
mybank.com.
86400
mybank.com.
86400
IN
IN
NS
NS
ns1.mybank.com.
ns2.mybank.com.
ns1.mybank.com.
604800
ns2.mybank.com.
604800
IN
IN
A
A
192.0.2.20
192.0.2.30
hohe TTL
falsche IP Adressen
Fragment 1
Fragment 2
IP-Fragment-Angriff
• einige Betriebssysteme (Windows, FreeBSD) benutzen eine sequentielle Fragment-ID
• die nächste Fragment-ID kann vom Angreifer erraten werden
DNSSEC to the rescue ...
“Men in the middle” Angriffe
• ein Angrifer kann DNS-Daten auf dem Weg ändern
www.example.com.
A 192.0.2.10
ISP
www.example.com.
A 192.0.2.10
authoritative DNS
Server
attacker
query for
www.example.com.
www.example.com.
A 10.1.2.3
Cache
query for
www.example.com.
client
resolver
“Verrat” des lokalen DNS Resolvers
• der Betreiber des DNS Resolvers (öffentliches WLAN) hat volle Kontrolle über die DNS Namensauflösung
www.example.com.
A 192.0.2.10
insecure/compromised
attacker
authoritative DNS
Server
query for
www.example.com.
www.example.com.
A 10.1.2.3
Cache
query for
www.example.com.
client
resolver
Angreifer kann lokale DNS Resolver Einstellungen ändern
• wie z.B. beim “Ghostclick-Network” geschehen
attackers
attacker has control over this resolving DNS Server
authoritative DNS
Server
attacker changes DNS resolver configuration on the client
attacker
www.example.com.
A 10.1.2.3
ISP/company
resolving
DNS Server
query for
www.example.com.
client
resolver
Angriffe auf den authoritativen DNS Server
• Der Angreifer kann die Daten auf dem authoritativen DNS Server ändern
www.example.com.
A 10.1.2.3
authoritative DNS
Server
query for
www.example.com.
www.example.com.
A 10.1.2.3
Cache
attacker
query for
www.example.com.
client
resolver
DNSSEC
History of DNSSEC
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
DNS being used in the Internet
History of DNSSEC
Steve Bellovin discovers flaw in DNS
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
work on DNSSEC started in the IETF
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
RFC2535
DNSSEC v1 is ready
History of DNSSEC
1983
1988
work on DNSSECbis started
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
RFC2535
DNSSEC v1 is ready
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
RFC2535
DNSSEC v1 is ready
March 2005:
RFC4033-4035 are published: DNSSEC v2
History of DNSSEC
1983
1988
1990 1995
October 2005: .SE signed
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
RFC2535
DNSSEC v1 is ready
March 2005:
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
RFC2535
DNSSEC v1 is ready
March 2005:
RFC 5155: NSEC3
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
DNSSEC
DNS
invented
root zone is signed
RFC2535
DNSSEC v1 is ready
March 2005:
RFC 5155: NSEC3
History of DNSSEC
1983
1988
1990 1995
1999 2001
2005
2008
2010
2012
DNSSEC
DNS
invented
root zone is signed
Windows 2012 DNSSEC
DANE RFC
RFC2535
DNSSEC v1 is ready
March 2005:
RFC 5155: NSEC3
DNS Security Extensions
• DNSSEC deployment (http://www.internetsociety.org/deploy360/dnssec/maps)
http://en.wikipedia.org/wiki/List_of_Internet_top-level_domains
• DNSSEC growth http://secspider.cs.ucla.edu/pix/growth.png
• DNSSEC delegations in NL:
https://xs.powerdns.com/dnssec-nl-graph/
Public-Key Kryptographie
k1
k2
plain
text
k1
k2
plain
text
encrypt
k1
k2
plain
text
cipher
text
encrypt
k1
k2
plain
text
cipher
text
encrypt
k1
k2
plain
text
cipher
text
encrypt
k1
cipher
text
k2
plain
text
cipher
text
encrypt
k1
cipher
text
decrypt
k2
plain
text
cipher
text
encrypt
k1
cipher
text
plain
text
decrypt
k2
Öffentlicher und Privater Schlüssel
• Der private Schlüssel wird sicher gespeichert (nicht auf einem Server mit direktem Kontakt zum Internet!)
• Der öffentliche Schlüssel wird als DNSKEY Record in der DNS Zone veröffentlicht
DNSSEC in einem Bild
authoritativer
DNS Server
DNS Resolver / Cache
authoritativer
DNS Server
plain
DNS data
authoritativer
DNS Server
plain
DNS data
hash
fingerprint
authoritativer
DNS Server
plain
DNS data
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
k
RRsig
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
k
RRsig
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
DNS Daten
fingerprint
Verschlüsselung
mit privatem
Schlüssel
RRsig
k
RRsig
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
DNS Daten
fingerprint
Verschlüsselung
mit privatem
Schlüssel
RRsig
k
öff. Schlüssel
RRsig
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
k
DNS Daten
plain DNS data
RRsig
RRsig
öff. Schlüssel
RRsig
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
RRsig
k
DNS Daten
plain DNS data
RRsig
RRsig
öff. Schlüssel
entschlüsseln
mit öff. Schlüssel
k
fingerprint
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
RRsig
k
DNS Daten
plain DNS data
RRsig
RRsig
öff. Schlüssel
entschlüsseln
fingerprint
k
hash
fingerprint
authoritativer
DNS Server
plain
DNS data
Zonefile
hash
fingerprint
Verschlüsselung
mit privatem
Schlüssel
RRsig
k
DNS Daten
plain DNS data
RRsig
RRsig
öff. Schlüssel
entschlüsseln
fingerprint
k
vergleichen
hash
fingerprint
DNSSEC Vertrauenskette
de. Zone
.DE zone privater Schlüssel
de. Zone
de.
de.
IN SOA (soa param)
IN RRSIG (SOA->DE-Key)
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
IN RRSIG (DNSKEY->DE-Key)
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
DNSKEY Record der .de Zone © Men & Mice http://menandmice.com Thursday 30 October 14
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
sub.de..
sub.de.
sub.de.
IN NS ns.example.de.
DNSKEY Record der .de Zone IN DS (hash->sub.DE-Key)
IN RRSIG (DS->DE-Key)
de. Zone
de. Zone
.de zone
Signaturen werden vom privaten Schlüssel erzeugt
(“DE”-Zone-Key)
Signatures
de. Zone
.de zone
(“DE”-Zone-Key)
Signatures
de. Zone
.de zone
(“DE”-Zone-Key)
Signatures
de. Zone
.de zone
(“DE”-Zone-Key)
.de Zone
nicht-authoritative Daten werden nicht signiert
(Delegation von sub.de)
Signatures
de. Zone
de.
de.
IN SOA (soa param)
.de zone
(“DE”-Zone-Key)
.de Zone
Signatures
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
.de zone
(“DE”-Zone-Key)
.de Zone
Signatures
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
sub.de..
sub.de.
sub.de.
IN DS (hash->sub.DE-Key)
.de zone
(“DE”-Zone-Key)
.de Zone
de. Zone
sub.de. Zone
sub.de privater DNSSEC Schlüssel signiert die Zonen-Daten
de. Zone
sub.de. Zone
de. Zone
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
IN RRSIG (SOA->SUB.DE-Key)
sub.de.
sub.de.
IN DNSKEY SUB.DE-Key
IN RRSIG (DNSKEY->SUB.DE-Key)
sub.de.
sub.de.
IN RRSIG (NS->SUB.DE-Key)
de. Zone
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
der DS-Record in der DE-Zone validiert den öffentlichen Schlüssel
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
de.
de.
IN SOA (soa param)
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
de. Zone
de.
de.
IN SOA (soa param)
de.
de.
IN DNSKEY de-Key
sub.de..
sub.de.
sub.de.
IN DS (hash->sub.DE-Key)
sub.de. Zone
sub.de.
sub.de.
IN SOA (soa param)
sub.de.
sub.de.
sub.de.
sub.de.
DNSSEC inline signing (aka BIND 9.9 Style)
Inline Signing
• BIND 9.9.0+ kann DNS Zonen während des Ladevorgangs signieren
• beim Laden der Zonendaten aus einer Datei
• beim Laden der Zonendaten per Zonentransfer von einem DNS Master Server
Inline Signing
DNSSERVER (master)
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
rndc reconfig
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
unsignierte
Zone
rndc reconfig
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
unsignierte
Zone
rndc sign
rndc reconfig
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
rndc reconfig
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
rndc sync
rndc reconfig
Zonendatei
(unsigniert)
Inline Signing
DNSSERVER (master)
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
rndc sync
rndc reconfig
Zonendatei
(unsigniert)
Zonendatei
signiert
(RAW-Format)
Inline Signing
DNSSERVER (master)
DNSSERVER (slave)
unsignierte
Zone
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
unsignierte
Zone
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
unsignierte
Zone
rndc sign
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
rndc sync
Inline Signing
DNSSERVER (slave)
DNSSERVER (master)
unsignierte
Zone
axfr/ixfr
Zonetransfer
unsignierte
Zone
rndc sign
DNSSEC
signierte
Zone
rndc sync
Zonendatei
signiert
(RAW-Format)
Inline Signing
// enable inline signing on a zone
zone "dnssec.dnslab.org" IN {
type master;
auto-dnssec maintain;
inline-signing yes;
file "dnssec.dnslab.org";
};
Inline Signing
type master;
auto-dnssec maintain;
inline-signing yes;
Inline-Signing anschalten
};
Inline Signing
automatische type master;
Signierung und Auffrischung der auto-dnssec maintain;
Signaturen
inline-signing yes;
Inline-Signing anschalten
};
Erzeugen der DNSSEC Schlüssel
# dnssec-keygen -K ./keys -a rsasha256 -b 2048 -n ZONE dnssec.example.de
# dnssec-keygen -K ./keys -a rsasha256 -b 2560 -f KSK -n ZONE dnssec.example.de
Zone signing key (ZSK)
Pfad zum Verzeichnis der DNSSEC Schlüssel
Algorithmus
Schlüssel-Stärke
Algorithmus
Schlüssel-Stärke
Name der Zone
Algorithmus
Die Zone signieren
# rndc sign dnssec.example.de
# tail -n2 /var/log/named.log
14-Nov-2011 21:58:37.945 zone dnssec.example.de/IN (unsigned): loaded serial 2
14-Nov-2011 21:58:37.946 zone dnssec.example.de/IN (signed): loaded serial 3 (DNSSEC signed)
Die Zone signieren
unsignierte Zone wird geladen
Die Zone signieren
unsignierte Zone wird geladen
signierte Zone wird geladen
Signierte Zonendatei lesbar machen
# rndc sync dnssec.example.de
# named-compilezone -f RAW
\
-o dnssec.example.de.txt \
dnssec.example.de dnssec.example.de.signed
letzte Änderungen an der Zonendatei in die Datei schreiben
\
letzte Änderungen an der Zonendatei in die Datei schreiben
\
Die Zonendatei vom Format RAW in das Text-Format umwandeln
DNSSEC Validierung
(vereinfacht)
DNSSEC Namensauflösung
“”
org.
example.org.
http://www.example.org.
local caching + validating DNS Server
© Men & Mice http://menandmice.com DNSSEC Namensauflösung
“”
org.
What is the address of
www.example.org.
example.org.
“”
org.
example.org.
http://www.example.com.
“”
www.example.org.
org.
example.org.
“”
org.
example.org.
“”
Here is a list of “org.” Name Servers
org.
example.org.
“”
org.
example.org.
“”
www.example.org.
org.
example.org.
“”
org.
example.org.
“”
Here is a list of “example.org.” Name Servers
org.
example.org.
“”
org.
example.org.
“”
org.
www.example.org.
example.org.
“”
org.
example.org.
“”
Here is the address of “www.example.org.” plus RRSIG (signatures)
org.
example.org.
“”
Here is the address of “www.example.org.” plus RRSIG (signatures)
Record
Function
www.example.org.A
IPv4 Address
www.example.org. RRSIG
signature ↑
org.
example.org.
“”
org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org.
“”
org.
What is the public key of
example.org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org.
“”
org.
example.org.
“”
Here is the DNSKEY of “example.org.” plus RRSIG (signatures)
org.
example.org.
“”
Here is the DNSKEY of “example.org.” plus RRSIG (signatures)
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
org.
example.org.
“”
org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org.
“”
What is the DS of
example.org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
org.
example.org.
“”
org.
example.org.
“”
Here is the “delegation signer (DS)” of “example.org.” + RRSIG
org.
example.org.
“”
Here is the “delegation signer (DS)” of “example.org.” + RRSIG
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org.
example.org.
“”
org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
example.org.
“”
What is the public key (DNSKEY) of
“org.”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org.
example.org.
“”
org.
example.org.
“”
Here is the public key (DNSKEY) of “org.” + RRSIG
org.
example.org.
“”
Here is the public key (DNSKEY) of “org.” + RRSIG
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org.
example.org.
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org.
example.org.
What is the DS of
“org.”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
“”
org.
example.org.
“”
org.
example.org.
Here is the “delegation signer (DS)” of “org.” + RRSIG
“”
org.
example.org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
Here is the “delegation signer (DS)” of “org.” + RRSIG
“”
org.
example.org.
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
org.
example.org.
Record
www.example.org.A
What is the public key (DNSKEY) of
Function
“.”
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
“”
org.
example.org.
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
org.
example.org.
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
Here is the public key (DNSKEY) of “.” + RRSIG
“”
org.
example.org.
“”
org.
example.org.
Trush Anchor for
“.” (root zone) from
configuration file
“”
org.
example.org.
Trush Anchor for
configuration file
“”
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
Trust Anchor for “.”
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
Record
Function
www.example.org.A
IPv4 Address
signature ↑
example.org. DNSKEY
public key
example.org. RRSIG
signature ↑
example.org. DS
hash of public key
org. RRSIG
signature ↑
org DNSKEY
public key
org RRSIG
signature ↑
org DS
hash of public key
. RRSIG
signature ↑
. DNSKEY
public key
. RRSIG
signature ↑
hash of public key
org.
example.org.
Trush Anchor for
configuration file
“”
org.
example.org.
“”
org.
Here is the address of “www.example.org.”
“Authenticated Data”
example.org.
“”
org.
Here is the address of “www.example.org.”
“Authenticated Data”
example.org.
© Men & Mice http://menandmice.com DNS Clients und DNS Resolver Kombinationen
DNS Clients und DNS Resolver Kombinationen
classic DNS
stub resolver
legacy DNS
resolver
classic DNS
stub resolver
legacy DNS
resolver
classic DNS
stub resolver
classic DNS
stub resolver
legacy DNS
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
classic DNS
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legacy DNS
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DNSSEC
validating
resolver
classic DNS
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DNSSEC aware
non-validating
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legacy DNS
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classic DNS
stub resolver
DNSSEC
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classic DNS
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DNSSEC
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resolver
DNSSEC aware
non-validating
stub-resolver
legacy DNS
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
legacy DNS
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
legacy DNS
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
DNSSEC
validating
resolver
legacy DNS
resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
DNSSEC
validating
resolver
legacy DNS
resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DNSSEC
validating
resolver
legacy DNS
resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RA
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RA
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
AA
DNSSEC
validating
resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DNSSEC
validating
resolver
RA
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DNSSEC
validating
resolver
RA
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
DNSSEC
validating
resolver
RD
RA
classic DNS
stub resolver
DO
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(not compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
insecure.com
(compromised)
AA
DO
AA
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
AA
DO
DNSSEC
validating
resolver
RD
RA
AA
RA
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
RA
DNSSEC
validating
Application
secure.org
(not compromised)
AA
DO
AA
RRSIG
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
DNSSEC
validating
resolver
RD
RA
AA
RRSIG
RA
AA
RRSIG
DO
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
RA
AD
RA
RRSIG
DNSSEC
validating
Application
secure.org
(compromised)
AA
DO
AA
RRSIG
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
SRVFAIL
AA
RRSIG
DO
DNSSEC
validating
resolver
RD
RA
AA
RRSIG
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
SRVFAIL
RA
RRSIG
DNSSEC
validating
Application
secure.org
(compromised)
AA
DO
AA
RRSIG
DNSSEC
validating
resolver
legacy DNS
resolver
RD
classic DNS
stub resolver
classic DNS
stub resolver
DO
SRVFAIL
AA
RRSIG
DO
DNSSEC
validating
resolver
RD
RA
AA
RRSIG
DNSSEC
validating
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RD
DO
CD
SRVFAIL
RA
RRSIG
DNSSEC
validating
Application
Windows 7 / 8
secure.org
(compromised)
AA
DO
IPsec
tunnel
legacy DNS
resolver
RD
DO
DNSSEC aware
non-validating
stub-resolver
RA
AD-Flag missing
on secure zone
= insecure DNS resolver
DNSSEC Validierung im Internet
DNSSEC im Internet
•
die DNS Root-Zone ist seit Sommer 2010 signiert
•
die meisten
ccTLDs und gTLDs sind DNSSEC signiert
•
Messungen* zeigen das 10-14% der DNS Anfragen per DNSSEC validiert
werden können
* http://gronggrong.rand.apnic.net/cgi-bin/worldmap
DNSSEC Validierung im Webbrowser
• DNSSEC und DANE Erweiterung
für Firefox, Google-Chrome,
Opera und Internet Explorer
(http://www.dnssec-validator.cz/) © Men & Mice http://menandmice.com Thursday 30 October 14
http://dnssec-or-not.org
http://dnssectest.sidn.nl
DANE
• RFC 6394: Use Cases and Requirements for DNS-Based Authentication of Named Entities (DANE)
• RFC 6698: The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA
• SSL/TLS Zertifikate durch DNSSEC absichern
DNSSEC sichert verschiedene Internet-Protokolle ab
•
Protokolle die über DNSSEC abgesichert werden können :
•
TLSA – HTTPS Zertifikate
•
SSHFP – ssh known_hosts Schlüssel-Fingerprints in DNS (RFC 4255 - in OpenSSH implementiert)
•
IPSECKEY – IPsec öffentliche RSA Schlüssel in DNS
•
CERT - GnuPG/PGP Schlüssel (RFC 4398)
•
OPENPGPKEY - GnuPG/PGP Schlüssel (neuer Draft)
•
S/MIME – S/MIME Schlüssel in DNS •
SMTP/TLSA – STARTSSL Zertifikate in DNS
•
SRV - service discovery
DANE acronyms
• RFC 7218 “Adding
Acronyms to Simplify Conversations
about DNS-Based Authentication of Named Entities
(DANE)” (April 2014)
der TLSA Record
shell> dig _443._tcp.bundy-dns.de tlsa +m +noall +answer
; <<>> DiG 9.9.4-P2 <<>> _443._tcp.bundy-dns.de tlsa +m +noall +answer
;; global options: +cmd
_443._tcp.example.com. 3581 IN TLSA 3 0 1 (
DD1B43FFD9672EE612529A1619CA24D27E22E51B1143
7BDBE56068CB57AE957B )
hash
algorithm
Port
transport
protocol
host
certificate
usage
selector
certificate
or hash
TLSA Record - Certificate usage
Value
Acronym
Description
0
PKIX-TA
CA constraint
1
PKIX-EE
Service certificate constraint
2
DANE-TA
Trust anchor assertion
3
DANE-EE
Domain-issued certificate
4-254
--
Unassigned
255
PrivCrt
Private Use
TLSA Record - Selectors
Value
Acronym
Description
0
Cert
Full certificate
1
SPKI
SubjectPublicKeyInfo
2-254
--
Unassigned
255
PrivSel
Private Use
TLSA Record - Matching Types
Value
Acronym
Description
0
Full
No hash used
1
SHA2-256
SHA2 256 bit hash
2
SHA2-512
SHA2 512 bit hash
3-254
--
Unassigned
255
PrivMatch
Private Use
TLSA Record mit ldns-dane
• einen TLSA-Record mit ldns-dane erzeugen:
# ldns-dane create www.example.com 443
_443._tcp.www.example.com. 3600IN TLSA3 0 1
aa0914c30428d804e92e1b68b38afea5b0e5721793f15fea60cf31fe44e275b7
TLSA manuell mittels OpenSSL
• TLSA tutorial:
http://blog.huque.com/2012/10/dnssec-and-certificates.html
• TLSA hash manuell erzeugen:
$ openssl x509 -in www.example.com.crt -outform DER | openssl sha256 (stdin)=
8cb0fc6c527506a053f4f14c8464bebbd6dede2738d11468dd953d7d6a3021f1
• TLSA Record:
_443._tcp.www.example.com. IN TLSA ( 3 0 1
d2abde240d7cd3ee6b4b28c54df034b9
7983a1d16e8a410e4561cb106618e971 )
TLSA mittels hash slinger erzeugen
• einen TLSA Record mittels hash-slinger erzeugen:
$ tlsa --create --output rfc --usage 3 --certificate example.crt www.example.com
_443._tcp.www.example.com. IN TLSA 3 0 1 (
8cb0fc6c527506a053f4f14c8464bebbd6dede2738d11468dd953d7d6a3021f1 )
• oder:
$ tlsa www.example.com
_443._tcp.www.example.com. IN TLSA 3 0 1 (
8cb0fc6c527506a053f4f14c8464bebbd6dede2738d11468dd953d7d6a3021f1 )
generate TLSA records
• TLSA-Generator:
https://www.huque.com/bin/gen_tlsa
• ldns-dane aus dem “ldns” Projekt
https://www.nlnetlabs.nl/projects/ldns/
• “hash-slinger” von Paul Wouters (Red Hat/Fedora):
http://people.redhat.com/pwouters/hash-slinger/
Vielen Dank
E-Mail:
[email protected]
[email protected]

TLS und SMTP - Strotmann.de

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