Today we have released PowerDNS Recursor 4.5.10, 4.6.3 and 4.7.2 due to a medium severity issue found. The security advisory only applies to Recursors running with protobuf logging enabled.
Please find the full text of the advisory below.
The changelogs are available at 4.5.10, 4.6.3, 4.7.2.
The source tarballs (4.5.10, 4.6.3, 4.7.2) and signatures (4.5.10, 4.6.3, 4.7.2) are available from our download server. Patches are available at patches. Packages for various distributions are available from our repository.
Note that PowerDNS Recursor 4.4.x and older releases are End of Life. Consult the EOL policy for more details.
PowerDNS Security Advisory 2022-02: incomplete exception handling related to protobuf message generation
This issue only affects recursors which have protobuf logging enabled using the
- protobufServer function with logResponses=true or
- outgoingProtobufServer function with logResponses=true
If either of these functions is used without specifying logResponses, its value is true.
An attacker needs to have access to the recursor, i.e. the remote IP must be in the access control list.
If an attacker queries a name that leads to an answer with specific properties, a protobuf message might be generated that causes an exception. The code does not handle this exception correctly, causing a denial of service.