USN-5232-1: Fail2ban vulnerability

12 September 2022

Fail2ban could be made to run programs as an administrator.

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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.

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Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

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Update instructions

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

Ubuntu 20.04
Ubuntu 18.04
Ubuntu 16.04
Ubuntu 14.04

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

References

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Further reading