RE: Re[2]: Windows DNS Cache Poisoning by Forwarder DNS Spoofing
Thanks for responding.
If this is the case, why is this report a report of a Windows DNS
vulnerability, since it appears to be a DNS (or at least BIND and
Windows) vulnerability? My guess is the original poster didn't include
BIND in his test scope or something like that.
Roger
*****************************************************************
*Roger A. Grimes, InfoWorld, Security Columnist
*CPA, CISSP, MCSE: Security (2000/2003/MVP), CEH, yada...yada...
*email: roger_grimes@xxxxxxxxxxxxx or roger@xxxxxxxxxxxxxx
*Author of Professional Windows Desktop and Server Hardening (Wrox)
*http://www.amazon.com/gp/product/0764599909
*****************************************************************
-----Original Message-----
From: 3APA3A [mailto:3APA3A@xxxxxxxxxxxxxxxx]
Sent: Tuesday, April 17, 2007 4:50 PM
To: Roger A. Grimes
Cc: Makoto Shiotsuki; bugtraq@xxxxxxxxxxxxxxxxx
Subject: Re[2]: Windows DNS Cache Poisoning by Forwarder DNS Spoofing
Dear Roger A. Grimes,
DNS spoofing attack in general can not be 'patched', because this is a
weakness of DNS protocol itself.
As for birthday attack applicability, this problem was discussed in
2002. In 2003 problem still exist in both bind 8 and 9. According to
CERT (US-CERT) as on 10/18/2004 bind was still vulnerable. As far as I
remember, there never was a patch for bind to prevent this specific
attack, yet it can be a part of some later bind release.
A possible mitigation against birthday attacks (not against spoofing in
general) on the server software level are any of:
1. Do no reuse source port for DNS requests. Have every request to be
issued from different source ports (resource consumption attack is
possible).
2. Keep a table of issued requests and do not issue request for the
same name before response for previous one is received (can not be
implemented in scalable 'multiple processes' DNS server architecture)
3. Monitor if multiple replies are received for a single request.
I don't know if bind actually use any. Hope, this helps.
--Tuesday, April 17, 2007, 8:48:04 PM, you wrote to shio@xxxxxxxxxxxx:
RAG> How does BIND stop this sort of attack?
RAG> Can a BIND expert respond?
RAG> Roger
RAG> *****************************************************************
RAG> *Roger A. Grimes, InfoWorld, Security Columnist *CPA, CISSP, MCSE:
RAG> Security (2000/2003/MVP), CEH, yada...yada...
RAG> *email: roger_grimes@xxxxxxxxxxxxx or roger@xxxxxxxxxxxxxx *Author
RAG> of Professional Windows Desktop and Server Hardening (Wrox)
RAG> *http://www.amazon.com/gp/product/0764599909
RAG> *****************************************************************
RAG> -----Original Message-----
RAG> From: Makoto Shiotsuki [mailto:shio@xxxxxxxxxxxx]
RAG> Sent: Tuesday, April 17, 2007 12:31 PM
RAG> To: Roger A. Grimes
RAG> Cc: bugtraq@xxxxxxxxxxxxxxxxx
RAG> Subject: Re: Windows DNS Cache Poisoning by Forwarder DNS Spoofing
>>One question. Is BIND any better at preventing this type of attack?
RAG> As far as I know, this vulnerability is specific to the Windows
DNS.
RAG> Makoto Shiotsuki
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