USN-3673-1: Unbound vulnerability

Releases

• Ubuntu 18.04 ESM
• Ubuntu 17.10
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• unbound - validating, recursive, caching DNS resolver

Details

Ralph Dolmans and Karst Koymans discovered that Unbound did not properly
handle certain NSEC records. An attacker could use this to to prove the
non-existence (NXDOMAIN answer) of an existing wildcard record, or trick
Unbound into accepting a NODATA proof.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 18.04

• libunbound2 - 1.6.7-1ubuntu2.1
• unbound - 1.6.7-1ubuntu2.1

Ubuntu 17.10

• libunbound2 - 1.6.5-1ubuntu0.2
• unbound - 1.6.5-1ubuntu0.2

Ubuntu 16.04

• libunbound2 - 1.5.8-1ubuntu1.1
• unbound - 1.5.8-1ubuntu1.1

Ubuntu 14.04

• libunbound2 - 1.4.22-1ubuntu4.14.04.3
• unbound - 1.4.22-1ubuntu4.14.04.3

In general, a standard system update will make all the necessary changes.

References

• CVE-2017-15105