1. Ubuntu Security Notices
  2. USN-5232-1

USN-5232-1: Fail2ban vulnerability

Publication date

12 September 2022

Overview

Fail2ban could be made to run programs as an administrator.

Releases

Packages

  • fail2ban - ban hosts that cause multiple authentication errors

Details

Jakub Żoczek discovered that certain Fail2ban actions handled whois responses in
an insecure way. If Fail2ban was configured to use certain mail actions
like ‘mail-whois’ on a target system, a remote attacker who was able to control whois
responses to this target system could possibly execute arbitrary code.

Jakub Żoczek discovered that certain Fail2ban actions handled whois responses in
an insecure way. If Fail2ban was configured to use certain mail actions
like ‘mail-whois’ on a target system, a remote attacker who was able to control whois
responses to this target system could possibly execute arbitrary code.

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
20.04 focal fail2ban –  0.11.1-1ubuntu0.1~esm1  
18.04 bionic fail2ban –  0.10.2-2ubuntu0.1~esm1  
16.04 xenial fail2ban –  0.9.3-1ubuntu0.1~esm1  
14.04 trusty fail2ban –  0.8.11-1ubuntu0.1~esm1  

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References

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