4.6 - USN-222-2

A security issue affects the following Ubuntu releases:

Ubuntu 4.10 (Warty Warthog) Ubuntu 5.04 (Hoary Hedgehog) Ubuntu 5.10 (Breezy Badger)

The following packages are affected:

libperl5.8 perl-base

The problem can be corrected by upgrading the affected package to version 5.8.4-2ubuntu0.6 (for Ubuntu 4.10), 5.8.4-6ubuntu1.2 (for Ubuntu 5.04), or 5.8.7-5ubuntu1.2 (for Ubuntu 5.10). In general, a standard system upgrade is sufficient to effect the necessary changes.

Details follow:

USN-222-1 fixed a vulnerability in the Perl interpreter. It was discovered that the version of USN-222-1 was not sufficient to handle all possible cases of malformed input that could lead to arbitrary code execution, so another update is necessary.

Original advisory:

Jack Louis of Dyad Security discovered that Perl did not
sufficiently check the explicit length argument in format strings.
Specially crafted format strings with overly large length arguments
led to a crash of the Perl interpreter or even to execution of
arbitrary attacker-defined code with the privileges of the user
running the Perl program.

However, this attack was only possible in insecure Perl programs
which use variables with user-defined values in string
interpolations without checking their validity.