Ubuntu 22.10 USN-5732-1 Critical Unbound Denial Of Service Attack

ubuntu

November 17, 2022

Unbound could be made to stop responding if it received specially crafted network traffic.

Summary

Unbound could be made to stop responding if it received specially crafted

network traffic.

Software Description:

- unbound: validating, recursive, caching DNS resolver

Details:

It was discovered that Unbound incorrectly handled delegations with a large

number of non-responsive nameservers. A remote attacker could possibly use

this issue to cause Unbound to consume resources, leading to a denial of

service.

Topics Covered

security advisory denial of service ubuntu network attack unbound

Update Instructions

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

Ubuntu 22.10:
   libunbound8                     1.16.2-1ubuntu0.1
   unbound                         1.16.2-1ubuntu0.1

Ubuntu 22.04 LTS:
   libunbound8                     1.13.1-1ubuntu5.3
   unbound                         1.13.1-1ubuntu5.3

Ubuntu 20.04 LTS:
   libunbound8                     1.9.4-2ubuntu1.4
   unbound                         1.9.4-2ubuntu1.4

Ubuntu 18.04 LTS:
   libunbound2                     1.6.7-1ubuntu2.6
   unbound                         1.6.7-1ubuntu2.6

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