170 likes | 436 Views
DNS 安全防護傘 - DNSSEC. 報告者:劉旭哲. 原因. 2008 駭客年會 Dan Kaminsky 公布重大安全漏洞「 DNS Cache Poisoning 」 雲端運算的興起. Normal DNS. Website. Internet. Master DNS. connect. connect. Update My Cache. Found it in my cache. Not Found in my cache. Query: B.com =?. Res: B.com=2.2.2.2. Query: B.com =?.
E N D
DNS安全防護傘 - DNSSEC 報告者:劉旭哲
原因 • 2008 駭客年會Dan Kaminsky公布重大安全漏洞「DNS Cache Poisoning」 • 雲端運算的興起
Normal DNS Website Internet Master DNS connect connect Update My Cache Found it in my cache Not Found in my cache Query: B.com =? Res: B.com=2.2.2.2 Query: B.com =? Query: A.com =? Res: A.com=1.1.1.1 Res: B.com=2.2.2.2 Cache Local DNS User
DNSCache Poisoning When I found it… When I’m looking for… If I was same as the original C.com, it’s easy to get info about user Fake C.com Internet Master DNS Hacker Query: C.com = ? Update No use This user will connect to fake C.com Res:C.com = 4.4.4.4 Res:C.com = 3.3.3.3 Query: C.com = ? Cache Local DNS User
Why need DNSSEC? • VeriSign發布的「2010年第二季度域名行業報告」 • .com .net網域總數破億,比第一季增加2% • VeriSign 的DNS查詢量每天625億次,最高峰每天836億次,均較以往提高超過15%
Forrester 調查發現,297名IT決策者中 • 51%遇到過DNS相關攻擊 • 38%遭遇到中間人攻擊
DNS Security Extensions • DNSSEC = DNS+digital signature • RFC4034 & RFC4035 • 新增四種RRsets • DNS Public Key (DNSKEY) • Resource Record Signature (RRSIG) • Next Secure (NSEC) • Delegation Signer (DS) -optionally
DNS Public Key (DNSKEY) • 公布Public key的地方 固定為三
For example • example.com. 86400 IN DNSKEY 256 3 5 ( AQP…………….== ) • Owner name TTL class RRtype Flag Pro. Algo. (PK)
Resource Record Signature (RRSIG) • digital signature Root = 0
Algo. • host.example.com. 86400 IN RRSIG A 5 3 86400 20030322173103 ( 20030220173103 2642 example.com. oJB1W6WNGv+ldvQ3WDG0MQkg5IEhjRip8WTrPYGv07h108dUKGMeDPKijVCHX3DDKdfb+v6o9wfuh3DTJXUAfI/M0zmO/zz8bW0Rznl8O3t GNazPwQKkRN20XPXV6nwwfoXmJQbsLNrLfkG J5D6fwFm8nN+6pBzeDQfsS3Ap3o= ) Key Tag Signer’s name Base64 Encoding
Next Secure (NSEC) • If next domain name doesn’t exist, itwill be the first domain name. • chain
alfa.example.com. 86400 IN NSEC host.example.com. ( A MX RRSIG NSEC TYPE1234 )
Delegation Signer (DS) • Protect user get right PK • Let upper manager sign 1(SHA-1)
dskey.example.com. 86400 IN DNSKEY 256 3 5 ( AQO……….== ) ; key id = 60485 • dskey.example.com. 86400 IN DS 60485 5 1 ( 2BB183AF5F22588179A53B0A 98631FAD1A292118 ) SHA-1
目前現況 • VeriSign 與 美國商務部和ICANN合作 ,在root中部屬DNSSEC • 預計在年底完成.net的部屬 • 2011第一季在.com中實現DNSSEC
http://tech.hexun.com.tw/2010-09-27/125010169.html • http://www.isc.org/files/DNSSEC_in_6_minutes.pdf • http://www.informationsecurity.com.tw/article/article_detail.aspx?tv=13&aid=5886 • http://phorum.study-area.org/index.php?topic=60268.0 • http://www.ietf.org/rfc/rfc4035.txt • http://www.ietf.org/rfc/rfc4034.txt