file: Integer underflow

Background

file is a utility that guesses a file format by scanning binary data for patterns.

Description

Jean-Sebastien Guay-Leroux reported an integer underflow in file_printf function.

Impact

A remote attacker could entice a user to run the “file” program on a specially crafted file that would trigger a heap-based buffer overflow possibly leading to the execution of arbitrary code with the rights of the user running “file”. Note that this vulnerability could be also triggered through an automatic file scanner like amavisd-new.

Workaround

There is no known workaround at this time.

Resolution

Since file is a system package, all Gentoo users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=sys-apps/file-4.20"