Multiple Cisco Products Vulnerable to DNS Cache Poisoning Attacks
Medium Nessus Plugin ID 49017
SynopsisThe remote device is missing a vendor-supplied security patch.
DescriptionMultiple Cisco products are vulnerable to DNS cache poisoning attacks due to their use of insufficiently randomized DNS transaction IDs and UDP source ports in the DNS queries that they produce, which may allow an attacker to more easily forge DNS answers that can poison DNS caches.
To exploit this vulnerability an attacker must be able to cause a vulnerable DNS server to perform recursive DNS queries. Therefore, DNS servers that are only authoritative, or servers where recursion is not allowed, are not affected.
Cisco has released free software updates that address these vulnerabilities.
SolutionApply the relevant patch referenced in Cisco Security Advisory cisco-sa-20080708-dns.