Ubuntu 21.04 USN-4976-1: Dnsmasq Cache Poisoning Threat

ubuntu

June 2, 2021

Dnsmasq could be exposed to cache poisoning.

Summary

Dnsmasq could be exposed to cache poisoning.

Software Description:

- dnsmasq: Small caching DNS proxy and DHCP/TFTP server

Details:

Petr Mensik discovered that Dnsmasq incorrectly randomized source ports in

certain configurations. A remote attacker could possibly use this issue to

facilitate DNS cache poisoning attacks.

Topics Covered

security advisory security issue Ubuntu remote threat update instructions cache poisoning dnsmasq

Update Instructions

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

Ubuntu 21.04:
  dnsmasq                         2.84-1ubuntu2.1
  dnsmasq-base                    2.84-1ubuntu2.1
  dnsmasq-utils                   2.84-1ubuntu2.1

Ubuntu 20.10:
  dnsmasq                         2.82-1ubuntu1.3
  dnsmasq-base                    2.82-1ubuntu1.3
  dnsmasq-utils                   2.82-1ubuntu1.3

Ubuntu 20.04 LTS:
  dnsmasq                         2.80-1.1ubuntu1.4
  dnsmasq-base                    2.80-1.1ubuntu1.4
  dnsmasq-utils                   2.80-1.1ubuntu1.4

Ubuntu 18.04 LTS:
  dnsmasq                         2.79-1ubuntu0.4
  dnsmasq-base                    2.79-1ubuntu0.4
  dnsmasq-utils                   2.79-1ubuntu0.4

After a standard system update you need to reboot your computer to make
all the necessary changes.