USN-3493-1: Exim vulnerability

Ubuntu Security Notice USN-3493-1

27th November, 2017

exim4 vulnerability

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 17.10
  • Ubuntu 17.04

Summary

Exim could be made to crash or run programs if it received specially crafted network traffic.

Software description

  • exim4 - Exim is a mail transport agent

Details

It was discovered that Exim incorrectly handled memory in the ESMTP
CHUNKING extension. A remote attacker could use this issue to cause Exim to
crash, resulting in a denial of service, or possibly execute arbitrary
code. The default compiler options for affected releases should reduce the
vulnerability to a denial of service.

Update instructions

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

Ubuntu 17.10:
exim4-daemon-heavy 4.89-5ubuntu1.1
exim4-daemon-light 4.89-5ubuntu1.1
Ubuntu 17.04:
exim4-daemon-heavy 4.88-5ubuntu1.2
exim4-daemon-light 4.88-5ubuntu1.2

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2017-16943