USN-1065-1: shadow vulnerability

15 February 2011

shadow vulnerability

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

  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 9.10


Newline injection possible into /etc/passwd

Software Description

  • shadow - system login tools


Kees Cook discovered that some shadow utilities did not correctly validate user input. A local attacker could exploit this flaw to inject newlines into the /etc/passwd file. If the system was configured to use NIS, this could lead to existing NIS groups or users gaining or losing access to the system, resulting in a denial of service or unauthorized access.

Update instructions

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

Ubuntu 10.10
passwd - 1:
Ubuntu 10.04 LTS
passwd - 1:
Ubuntu 9.10
passwd - 1:

To update your system, please follow these instructions:

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