Andreas Steffen, , 12-DNSSEC.pptx 1 Internet Security 1 (IntSi1) Prof. Dr. Andreas Steffen Institute for Internet Technologies and Applications (ITA) 12 DNS Security Extensions DNSSEC

Andreas Steffen, , 12-DNSSEC.pptx 2 DNS Resolution via Recursive Nameserver

Andreas Steffen, , 12-DNSSEC.pptx 3 DNS Request

Andreas Steffen, , 12-DNSSEC.pptx 4 DNS Response

Andreas Steffen, , 12-DNSSEC.pptx 5 Simple DNS Cache Poisoning

Andreas Steffen, , 12-DNSSEC.pptx 6 Guessing Query ID and UDP Source Port

Andreas Steffen, , 12-DNSSEC.pptx 7 The Dan Kaminsky DNS Vulnerability – July 2008

Andreas Steffen, , 12-DNSSEC.pptx 8 DNS Root Servers A VeriSign Inc. B C D E F G H I J K L M Information Sciences Institute, USC OperatorIPv IPv6 2001:503:BA3E::2:30 # 2001:478:65:: :500:2F::F :500:1::803F: :7FE:: :503:C27::2: :7FD::1 2001:500:3:: :DC3::35 Cogent Communications University of Maryland1 NASA Ames Research Center1 Internet Systems Consortium Inc.49 US DoD Network Information Center6 US Army Research Lab1 Autonomica/NORDUnet34 VeriSign Inc.70 RIPE NCC18 ICANN3 WIDE Project6 200 Total number of servers:

Andreas Steffen, , 12-DNSSEC.pptx 9 Global Map of Root Servers

Andreas Steffen, , 12-DNSSEC.pptx 10 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. A x.x.x.x ZSK switch.ch. NS ns1/ns2 ZSKKSK/ZSK root DNSKEY (ZSK)

Andreas Steffen, , 12-DNSSEC.pptx 11 DNSSEC Resource Records I - DNSKEY DNSKEY - DNS Public Key Contains a public key used to sign the RRsets of a zone switch.ch IN DNSKEY AwEAAeCDWwjJO4mXBzayiKf4p7waJ7Ew eUnsTsAWkxpfELci4iaVdBugzYPfsZIg 9R6TIPky3LoPAPmIjCc2fbFkKnrGI7hJ jXAGMRwRJIBprFx4BXZSsjsvGb6MGC+e xHSlXw== ;{id = (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

Andreas Steffen, , 12-DNSSEC.pptx 12 DNSSEC Resource Records II - RRSIG RRSIG - Resource Record Signature Contains a public key signature over a resource record set (RRset) merapi.switch.ch IN A merapi.switch.ch IN RRSIG A 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.

Andreas Steffen, , 12-DNSSEC.pptx 13 DNSSEC Resource Records III - DS DS - Delegation Signer Signed hash computed over KSK of child zone switch.ch IN DS dcfca519cf8b cc switch.ch IN DS cef df83311a92b48ae7f19 1ae e38b1ab7b3d0966b9ee55 switch.ch IN RRSIG DS ch. LPh8RgXQSqPcdQz6s1PJOjTuopO9RxQg s1YYCY/CnhYaHxb6ndNBJ7QP20eKN+91 /ULjN4Ep/k9Pgtos979i5OfEXpfLcWcv rKP1xGvqW4PjP+MT1PDs6uKisEUqGBoQ p7+nkkzjY+YsDbxtTV+/8uHcSnNmXoMm SqPms3G0aw4= ;{id = 31034}

Andreas Steffen, , 12-DNSSEC.pptx 14 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 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!!!

Andreas Steffen, , 12-DNSSEC.pptx 15 DNSSEC Resource Records V - NSEC3 NSEC3 – Next Owner Name in Hashed Order Hashed Authenticated Denial of Existence h9p7u7tr2u91d0v0ljs9l1gidnp90u3h.org. 691 IN NSEC d399eaab h9rsfb7fpf2l8hg35cmpc765tdk23rp6 NS SOA RRSIG DNSKEY NSEC3PARAM ; flags: optout h9p7u7tr2u91d0v0ljs9l1gidnp90u3h.org. 691 IN RRSIG NSEC 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.

Andreas Steffen, , 12-DNSSEC.pptx 16 DNSSEC Root Zone Signing Process ICANN Vetting and Processing TLD Operator DS Records DoC NTIA Authorization of Changes DS Records VeriSign Editing and Signing of Root Zone DS Records Root Servers (A,..., M) DS Records Root ZSK ZSK

Andreas Steffen, , 12-DNSSEC.pptx 17 DNSSEC Root Zone Signing Key Signing Process VeriSign ZSK Management ZSK Private Key ZSK ICANN KSK Management KSR Key Signing Request KSK Private Key KSK Published on Web Site ZSK KSK SKR Signed Key Response

Andreas Steffen, , 12-DNSSEC.pptx 18 ICANN Key Ceremonies Tier 1 – Facility – Access Control by Data Center Tier 2 – Facility – Access Control by Data Center Tier 3 – 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 Ceremony Computer

Andreas Steffen, , 12-DNSSEC.pptx 19 ICANN Key Ceremonies

Andreas Steffen, , 12-DNSSEC.pptx 20 Periodic Key Rollover T-10T+0T+10T+20T+30T+40T+50T+60T+70T+80T+90 ZSK post-publish ZSK pre-publish ZSK post-publish ZSK pre-publish ZSK KSK publish+sign KSK publish+sign KSK publish+sign KSK publish+sign KSK publish+sign KSK publish+sign KSK publish+sign KSK revoke+sign KSK revoke+sign KSK publish KSK publish KSK publish KSK publish KSK publish KSK publish+sign KSK publish+sign KSK publish+sign KSK publish+sign ZSK Rollover (every 90 days) Optional KSK Rollover (every 2-5 years or on demand) RRSIG Validity Period (10 days + 50% overlap)

Andreas Steffen, , 12-DNSSEC.pptx 21 DNSSEC Deployment (November ) 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 ( Sinhala Sri Lanka) xn--xkc2al3hye2a ( இலங்கை Tamil Sri Lanka) Signing of major gTLDs: net: December 9, 2010 com: March 2011