USN-4446-2: Squid regression

27 August 2020

USN-4446-1 introduced a regression in Squid.

Releases

Packages

  • squid3 - Web proxy cache server

Details

USN-4446-1 fixed vulnerabilities in Squid. The update introduced a
regression when using Squid with the icap or ecap protocols. This update
fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Jeriko One discovered that Squid incorrectly handled caching certain
requests. A remote attacker could possibly use this issue to perform
cache-injection attacks or gain access to reverse proxy features such as
ESI. (CVE-2019-12520)

Jeriko One and Kristoffer Danielsson discovered that Squid incorrectly
handled certain URN requests. A remote attacker could possibly use this
issue to bypass access checks. (CVE-2019-12523)

Jeriko One discovered that Squid incorrectly handled URL decoding. A remote
attacker could possibly use this issue to bypass certain rule checks.
(CVE-2019-12524)

Jeriko One and Kristoffer Danielsson discovered that Squid incorrectly
handled input validation. A remote attacker could use this issue to cause
Squid to crash, resulting in a denial of service. (CVE-2019-18676)

Update instructions

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

Ubuntu 18.04
Ubuntu 16.04

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