Date: Wed, 7 Jun 2000 16:21:17 -0700
From: FreeBSD Security Advisories security-advisories@freebsd.org
To: BUGTRAQ@SECURITYFOCUS.COM
Subject: FreeBSD Security Advisory: FreeBSD-SA-00:22.apsfilter
FreeBSD-SA-00:22 Security Advisory
FreeBSD, Inc.
Topic: apsfilter allows users to execute arbitrary commands as
user lpd
Category: ports
Module: apsfilter
Announced: 2000-06-07
Credits: Fixed by vendor.
Affects: Ports collection.
Corrected: 2000-04-29
Vendor status: Updated version released.
FreeBSD only: NO
I. Background
apsfilter is a print filter which automatically handles the
conversion of various types of file into a format understood by the
printer.
II. Problem Description
The apsfilter port, versions 5.4.1 and below, contain a
vulnerability which allow local users to execute arbitrary commands
as the user running lpd, user root in a default FreeBSD
installation. The apsfilter software allows users to specify their
own filter configurations, which are read in an insecure manner and
may be used to elevate privileges.
The apsfilter port is not installed by default, nor is it “part
of FreeBSD” as such: it is part of the FreeBSD ports collection,
which contains over 3300 third-party applications in a
ready-to-install format. The ports collection shipped with FreeBSD
4.0 contains this problem since it was discovered after the
release.
FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.
III. Impact
Local users can cause arbitrary commands to be executed as
root.
If you have not chosen to install the apsfilter port/package,
then your system is not vulnerable to this problem.
IV. Workaround
Deinstall the apsfilter port/package, if you you have installed
it.
V. Solution
One of the following:
1) Upgrade your entire ports collection and rebuild the
apsfilter port.
2) Deinstall the old package and install a new package dated
after the correction date, obtained from:
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/print/apsfilter-5.4.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/print/apsfilter-5.4.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/print/apsfilter-5.4.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/print/apsfilter-5.4.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/print/apsfilter-5.4.2.tgz
3) download a new port skeleton for the apsfilter port from:
and use it to rebuild the port.
4) Use the portcheckout utility to automate option (3) above.
The portcheckout port is available in /usr/ports/devel/portcheckout
or the package can be obtained from:
ftp://ftp.freebsd.org/pub/FreeBSD/ports/packages/devel/portcheckout-1.0.tgz