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AUSCERT External Security Bulletin Redistribution
ESB-2001.170 -- FreeBSD-SA-01:34.hylafax
hylafax contains local compromise
26 April 2001
AusCERT Security Bulletin Summary
Vendor: FreeBSD Ports Collection
Operating System: FreeBSD
Impact: Root Compromise
Access Required: Existing Account
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FreeBSD-SA-01:34 Security Advisory
Topic: hylafax contains local compromise
Credits: Marcin Dawcewicz <miv@IIDEA.PL>
Affects: Ports collection prior to the correction date.
Vendor status: Updated version released
FreeBSD only: NO
HylaFAX is a facsimile system for UNIX systems.
II. Problem Description
The hylafax port, versions prior to hylafax-4.1.b2_2, contains a
format string bug in the hfaxd program. A local user may execute
the hfaxd program with command-line arguments containing format string
characters, potentially gaining root privileges on the local system.
The hylafax 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 5000 third-party applications in a ready-to-install
format. The ports collections shipped with FreeBSD 3.5.1 and 4.2
contain this problem since it was discovered after the releases.
The ports collection that shipped with FreeBSD 4.3 is not vulnerable
since this problem was corrected prior to 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.
Local users may gain root privileges on the local system.
If you have not chosen to install the hylafax port/package, then your
system is not vulnerable to this problem.
Deinstall the hylafax port/package if you have installed it.
One of the following:
1) Upgrade your entire ports collection and rebuild the hylafax port.
2) Deinstall the old package and install a new package dated after the
correction date, obtained from:
NOTE: it may be several days before updated packages are available.
Packages are not automatically generated for the alpha architecture at
this time due to lack of build resources.
3) download a new port skeleton for the hylafax 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:
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