BIND DNS Query Port Entropy Weakness

As a few days ago a vulnerability was reported in BIND. A remote user can spoof the system.

The domain name system (DNS) service does not use sufficiently random UDP sockets to process queries. A remote user can send specially crafted DNS queries and responses to the target service to spoof responses and insert records into the DNS cache. This may cause traffic to be redirected to arbitrary IP addresses specified by the remote user.

The vendor indicates that the vulnerability exists in the DNS protocol itself, rather than in any particular vendor’s implementation.

Systems using BIND as a caching resolver are affected.

Some demonstration exploit code is available at:
http://www.caughq.org/exploits/CAU-EX-2008-0002.txt
http://www.caughq.org/exploits/CAU-EX-2008-0003. txt

Dan Kaminsky of IOActive reported this vulnerability.
Impact: A remote user can spoof the DNS service, causing traffic to be redirected to arbitrary hosts.
Solution: The vendor has issued patches (9.5.0-P1, 9.4.2-P1, 9.3.5-P1). New beta releases (9.5.1b1, 9.4.3b2) are also available.

The software is available at:
http://www.isc.org/index.pl?/menu.pl?sect=sw

The vendor reports that the fix provides increased resilience to the attack, but that “DNSSEC is the only full solution.”

In conclusion just check your bind(named) version and upgrade the application asap if you don’t want to have any issues.

Source: SecurityTracker

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