Successfully poisoned the latest BIND with fully randomized ports!
Exploit required to send more than 130 thousand of requests for the fake records like
131737-4795-15081.blah.com to be able to match port and ID and insert poisoned entry
for the poisoned_dns.blah.com.
# dig @localhost www.blah.com +norecurse
; <<>> DiG 9.5.0-P2 <<>> @localhost www.blah.com +norecurse
; (1 server found)
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6950
;; flags: qr ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;www.blah.com. IN A
;; AUTHORITY SECTION:
www.blah.com. 73557 IN NS poisoned_dns.blah.com.
;; ADDITIONAL SECTION:
poisoned_dns.blah.com. 73557 IN A 188.8.131.52
# named -v
BIND used fully randomized source port range, i.e. around 64000 ports.
Two attacking servers, connected to the attacked one via GigE link, were used,
each one attacked 1-2 ports with full ID range. Usually attacking server is able
to send about 40-50 thousands fake replies before remote server returns the
correct one, so if port was matched probability of the successful poisoning is more than 60%.
Attack took about half of the day, i.e. a bit less than 10 hours.
So, if you have a GigE lan, any trojaned machine can poison your DNS during one night...
original source: http://tservice.net.ru/~s0mbre/blog/2008/08/08/
# milw0rm.com [2008-08-13]