ISC reports:

A BIND 9 DNS server set up to be a caching resolver is vulnerable to a user querying a domain with very large resource record sets (RRSets) when trying to negatively cache a response. This can cause the BIND 9 DNS server (named process) to crash.

< 9.4.3.4

< 9.6.3.1.ESV.R4.1

< 9.7.3.1

< 9.8.0.2

ge 7.3 lt 7.3_6

ge 7.4 lt 7.4_2

ge 8.1 lt 8.1_4

ge 8.2 lt 8.2_2

Problem Description:

When named(8) receives a specially crafted dynamic update message an internal assertion check is triggered which causes named(8) to exit.

To trigger the problem, the dynamic update message must contains a record of type "ANY" and at least one resource record set (RRset) for this fully qualified domain name (FQDN) must exist on the server.

Impact:

An attacker which can send DNS requests to a nameserver can cause it to exit, thus creating a Denial of Service situation.

Workaround:

No generally applicable workaround is available, but some firewalls may be able to prevent nsupdate DNS packets from reaching the nameserver.

NOTE WELL: Merely configuring named(8) to ignore dynamic updates is NOT sufficient to protect it from this vulnerability.

< 9.3.6.1.1

< 9.4.3.3

ge 6.3 lt 6.3_12

ge 6.4 lt 6.4_6

ge 7.1 lt 7.1_7

ge 7.2 lt 7.2_3