andreas steffen, 28.11.2011, 12-dnssec.pptx 1 internet security 1 (intsi1) prof. dr. andreas steffen...

Andreas Steffen, 28.11.2011, 12-DNSSEC.pptx 1

Internet Security 1 (IntSi1)

Prof. Dr. Andreas Steffen

Institute for Internet Technologies and Applications (ITA)

12 DNS Security Extensions

DNSSEC


DNS Resolution via Recursive Nameserver


DNS Request


DNS Response


Simple DNS Cache Poisoning


Guessing Query ID and UDP Source Port


The Dan Kaminsky DNS Vulnerability – July 2008


DNS Root Servers

A VeriSign Inc.

B

C

D

E

F

G

H

I

J

K

L

M

Information Sciences Institute, USC

OperatorIPv4

198.41.0.4

192.228.79.201

192.33.4.12

128.8.10.90

192.203.230.10

192.5.5.241

192.112.36.4

128.63.3.53

192.36.148.17

192.58.128.30

193.0.14.129

199.7.83.42

202.12.27.33

IPv6

2001:503:BA3E::2:30

#

2001:478:65::53

-

-

-

2001:500:2F::F

-

2001:500:1::803F:235

2001:7FE::53

2001:503:C27::2:30

2001:7FD::1

2001:500:3::42

2001:DC3::35

Cogent Communications

4

1

6

University of Maryland 1

NASA Ames Research Center 1

Internet Systems Consortium Inc. 49

US DoD Network Information Center6

US Army Research Lab 1

Autonomica/NORDUnet 34

VeriSign Inc. 70

RIPE NCC 18

ICANN 3

WIDE Project 6

200Total number of servers:


Global Map of Root Servers


root DNSKEY (KSK)*

* explicit import e.g. via trusted web site

ch. DNSKEY (KSK)

ZSK

ch. DS

DNSSEC Chain of Trust

root

KSK/ZSK

ch. DNSKEY (ZSK)

ZSK

switch.ch. DS switch.ch. DNSKEY (KSK)

KSK/ZSK

switch.ch. DNSKEY (ZSK)

ch. switch.ch.

www.switch.ch. A x.x.x.x

ZSK

switch.ch. NS ns1/ns2

ZSK

KSK/ZSK

root DNSKEY (ZSK)


DNSSEC Resource Records I - DNSKEY

• DNSKEY - DNS Public Key• Contains a public key used to sign the RRsets of a zone

switch.ch. 81154 IN DNSKEY 256 3 5 AwEAAeCDWwjJO4mXBzayiKf4p7waJ7Ew eUnsTsAWkxpfELci4iaVdBugzYPfsZIg 9R6TIPky3LoPAPmIjCc2fbFkKnrGI7hJ jXAGMRwRJIBprFx4BXZSsjsvGb6MGC+e xHSlXw== ;{id = 64608 (zsk), size = 768b}

• Flags field• 256 -> Zone Signing Key (ZSK)• 257 -> Key Signing Key (KSK) with secure entry point (SEP)

flag set

• Algorithm field• 5 -> SHA-1 with RSA• 7 -> SHA-1 with RSA & NSEC3 with SHA-1• 8 -> SHA-256 with RSA• 10 -> SHA-512 with RSA


DNSSEC Resource Records II - RRSIG

• RRSIG - Resource Record Signature• Contains a public key signature over a resource record set

(RRset)

merapi.switch.ch. 172800 IN A 130.59.211.10

merapi.switch.ch. 172800 IN RRSIG A 5 3 172800 20091128231033 20091029231033 64608 switch.ch.

3KW9YjxdL08FqVYKFSn9 Q4+8U1iYrVCun+J1Ny8Y IiMC+6oQS/GZwRn2mr+H MruwEjNB9s7bWGzRmRiR TATPvS67gxjCiJkSP58P kGJ1dW3wBaz6r1feGNvz KhHLhvRe ;{id = 64608}

• Signature Expiration and Inception Fields• The signature is not valid before Inception and after

Expiration date.

• Key Tag Field• Contains the key tag of the key which signed the RRset.


DNSSEC Resource Records III - DS

• DS - Delegation Signer• Signed hash computed over KSK of child zone

switch.ch. 3364 IN DS 43837 5 1 91dcfca519cf8b038441869878cc3610 60200534 switch.ch. 3364 IN DS 43837 5 2 838cef7635952df83311a92b48ae7f19 1ae29484534e38b1ab7b3d0966b9ee55

switch.ch. 3416 IN RRSIG DS 7 2 3600 20091123183442 20091117220724 31034 ch. LPh8RgXQSqPcdQz6s1PJOjTuopO9RxQg s1YYCY/CnhYaHxb6ndNBJ7QP20eKN+91 /ULjN4Ep/k9Pgtos979i5OfEXpfLcWcv rKP1xGvqW4PjP+MT1PDs6uKisEUqGBoQ p7+nkkzjY+YsDbxtTV+/8uHcSnNmXoMm SqPms3G0aw4= ;{id = 31034}


DNSSEC Resource Records IV - NSEC

• NSEC – Next Owner Name• Authenticated denial of existence of an owner name

merapi.switch.ch. 180 IN NSEC mercury.switch.ch. A PTR AAAA LOC RRSIG NSEC

merapi.switch.ch. 180 IN RRSIG NSEC 5 3 180 20091128231033 20091029231033 64608 switch.ch. kW1SnXWoJKwOHEG1P3INI83EOGuQ GujwvBT/MSWVQ+ms/2DXxjQcpt1Z P07+XI51cc0t7erUUG31KZdmUpXZ tQzPUJh49jjLh9aTjRiH1xGhlxv5 af+N95JDykRGSOAq ;{id = 64608}

• Proof that there is no name between merapi.switch.ch. and mercury.switch.ch.

• Allows enumeration of complete zone data!!!


DNSSEC Resource Records V - NSEC3

• NSEC3 – Next Owner Name in Hashed Order• Hashed Authenticated Denial of Existence

h9p7u7tr2u91d0v0ljs9l1gidnp90u3h.org. 691 IN NSEC3 1 1 1 d399eaabh9rsfb7fpf2l8hg35cmpc765tdk23rp6 NS SOA RRSIG DNSKEY NSEC3PARAM ; flags: optout

h9p7u7tr2u91d0v0ljs9l1gidnp90u3h.org. 691 IN RRSIG NSEC3 7 2 86400 20091202211702 20091118201702 5273 org. a+CC37hRM7yCFBaZn2SeRgY9h247GXptCuBYf45TwaoR xvBwTAXPT+UwZ/4hxwc2v7AR7ZZ8UOMiNJvYsl59eFW8 Xtgws4/Aih0fJ2/O8yUHwI695fRf9PrpxXEpqzStjSZP 5arJ1oldDAHcnxgLqdAMW6wnK1FNrslfJblJlmU= ;{id = 5273}

• Proof that there is no name between org. and ???.org.• Does not allow straight enumeration of zone data!• Dictionary attacks are possible but expensive.


DNSSEC Root Zone Signing Process

ICANN Vetting and Processing

TLD OperatorDS

Records

DoC NTIA Authorization of Changes

DSRecord

s

VeriSign Editing and Signing of Root Zone

DSRecord

s

Root Servers (A, ... , M)

DSRecord

s

Root ZSK

ZSK


DNSSEC Root Zone Signing Key Signing Process

VeriSignZSK Management

ZSK Private Key

ZSK

ZSK

ICANNKSK Management

KSRKey Signing

Request

KSK Private Key

KSK

KSKPublished on Web

Site

ZSK

KSK

SKRSigned Key

Response


ICANN Key Ceremonies

Tier 1 – Facility – Access Control by Data Center



Tier 4 – Cage – Access Control by Data Center

Tier 5 – Safe Room – Access Control by ICANN

Tier 6 – Safe #1 Tier 6 – Safe #2

Tier 7 – Safe Deposit Box

Crypto Officers‘

Credentials

Tier 7 – HSM

KSK Private Keys

Key CeremonyComputer


ICANN Key Ceremonies


Periodic Key Rollover

T-10 T+0 T+10 T+20 T+30 T+40 T+50 T+60 T+70 T+80 T+90

ZSKZSKpost-

publishZSKpre-

publishZSK ZSK ZSK ZSK ZSK ZSK ZSK ZSK ZSK

ZSKpost-

publishZSKpre-

publishZSK

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKrevoke+sig

n

KSKrevoke+sig

n

KSKpublish

KSKpublish

KSKpublish

KSKpublish

KSKpublish

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

KSKpublish+sig

n

ZSK Rollover (every 90 days)

Optional KSK Rollover (every 2-5 years or on demand)

RRSIG Validity Period (10 days + 50% overlap)


DNSSEC Deployment (November 28 2011)

• TLDs signed by root zone:• 11 gTLDs: arpa asia biz cat com edu gov info museum net

org• 54 ccTLDS: ac ag am be bg br bz ch cl co cz de dk eu fi fr gi gl

gr hn in io jp kg kr la lc li lk lu me mn my na nc nl nu pm pr pt re sc se sh su tf th tm tw ug uk us wf yt

• 2 IDN ccTLDS: xn--kprw13d xn--kpry57d ( 台湾 Taiwan)

• TLDs with DNSKEY set:• 1 gTLD: mil• 3 ccTLDs: mm nz vc• 2 IDN ccTLDs: xn--fzc2c9e2c (ලං�කා� Sinhala Sri Lanka)

xn--xkc2al3hye2a ( இலங்கை� Tamil Sri Lanka)

• Signing of major gTLDs:• net: December 9, 2010• com: March 2011

andreas steffen, 28.11.2011, 12-dnssec.pptx 1 internet security 1 (intsi1) prof. dr. andreas steffen...

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