1. Ubuntu Security Notices
  2. USN-5034-1

USN-5034-1: c-ares vulnerability

Publication date

10 August 2021

Overview

c-ares could be made to return wrong domains.

Releases

Packages

  • c-ares - library for asynchronous name resolution

Details

Philipp Jeitner and Haya Shulman discovered that c-ares incorrectly
validated certain hostnames returned by DNS servers. A remote attacker
could possibly use this issue to perform Domain Hijacking attacks.

Philipp Jeitner and Haya Shulman discovered that c-ares incorrectly
validated certain hostnames returned by DNS servers. A remote attacker
could possibly use this issue to perform Domain Hijacking attacks.

Update instructions

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
21.04 hirsute libc-ares2 –  1.17.1-1ubuntu0.1
20.04 focal libc-ares2 –  1.15.0-1ubuntu0.1
18.04 bionic libc-ares2 –  1.14.0-1ubuntu0.1

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References

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