USN-129-1: Squid vulnerability

18 May 2005

squid vulnerability

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

  • Ubuntu 5.04
  • Ubuntu 4.10

Software Description


It was discovered that Squid did not verify the validity of DNS server responses. When Squid is started, it opens a DNS client UDP port whose number is randomly assigned by the operating system. Unless your network firewall is configured to accept DNS responses only from known good nameservers, this vulnerability allowed users within the local network to inject arbitrary DNS responses into Squid (“DNS spoofing”). This could be used to present different web pages to users from those they actually requested.

Update instructions

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

Ubuntu 5.04
Ubuntu 4.10

To update your system, please follow these instructions: