pstopnm in netpbm does not properly use the "-dSAFER" option when calling Ghostscript to convert a PostScript file into a (1) PBM, (2) PGM, or (3) PNM file, which allows external user-assisted attackers to execute arbitrary commands.

Max Vozeler from the Debian Audit Project discovered that pstopnm, a converter from Postscript to the PBM, PGM and PNM formats, launches Ghostscript in an insecure manner, which might lead to the execution of arbitrary shell commands, when converting specially crafted Postscript files.

Updated netpbm packages that fix a security issue are now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The netpbm package contains a library of functions that support programs for handling various graphics file formats, including .pbm (portable bitmaps), .pgm (portable graymaps), .pnm (portable anymaps), .ppm (portable pixmaps) and others.

A bug was found in the way netpbm converts PostScript files into PBM, PGM or PPM files. An attacker could create a carefully crafted PostScript file in such a way that it could execute arbitrary commands when the file is processed by a victim using pstopnm. The Common Vulnerabilities and Exposures project assigned the name CVE-2005-2471 to this issue.

All users of netpbm should upgrade to the updated packages, which contain a backported patch to resolve this issue.

Max Vozeler discovered that the the 'pstopnm' conversion tool did not use the -dSAFER option when calling ghostscript. This option prohibits file operations and calling commands within PostScript code. This flaw could be exploited by an attacker to execute arbitrary code if he tricked an user (or an automatic server) into processing a specially crafted PostScript document with pstopnm.

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Max Vozeler discovered that pstopnm, a part of the netpbm graphics utility suite, would call the GhostScript interpreter on untrusted PostScript files without using the -dSAFER option when converting a PostScript file into a PBM, PGM, or PNM file. This could result in the execution of arbitrary commands with the privileges of the user running pstopnm if they could be convinced to try to convert a malicious PostScript file.

The updated packages have been patched to correct this problem.

The remote Redhat Enterprise Linux 4 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2005:743 advisory.

    The netpbm package contains a library of functions that support     programs for handling various graphics file formats, including .pbm     (portable bitmaps), .pgm (portable graymaps), .pnm (portable anymaps),     .ppm (portable pixmaps) and others.

    A bug was found in the way netpbm converts PostScript files into PBM, PGM     or PPM files.  An attacker could create a carefully crafted PostScript file     in such a way that it could execute arbitrary commands when the     file is processed by a victim using pstopnm.  The Common Vulnerabilities     and Exposures project assigned the name CAN-2005-2471 to this issue.

    All users of netpbm should upgrade to the updated packages, which     contain a backported patch to resolve this issue.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-200508-04 (Netpbm: Arbitrary code execution in pstopnm)

    Max Vozeler reported that pstopnm calls the GhostScript interpreter on     untrusted PostScript files without specifying the -dSAFER option, to     convert a PostScript file into a PBM, PGM, or PNM file.
  Impact :

    An attacker could craft a malicious PostScript file and entice a user     to run pstopnm on it, resulting in the execution of arbitrary commands     with the permissions of the user running pstopnm.
  Workaround :

    There is no known workaround at this time.

ID	Name	Product	Family	Severity
22563	Debian DSA-1021-1 : netpbm-free - insecure program execution	Nessus	Debian Local Security Checks	high
21958	CentOS 3 / 4 : netpbm (CESA-2005:743)	Nessus	CentOS Local Security Checks	high
20570	Ubuntu 4.10 / 5.04 : netpbm-free vulnerability (USN-164-1)	Nessus	Ubuntu Local Security Checks	high
19892	Mandrake Linux Security Advisory : netpbm (MDKSA-2005:133)	Nessus	Mandriva Local Security Checks	high
19488	RHEL 4 : netpbm (RHSA-2005:743)	Nessus	Red Hat Local Security Checks	critical
19388	GLSA-200508-04 : Netpbm: Arbitrary code execution in pstopnm	Nessus	Gentoo Local Security Checks	high

Detections

Analytics

CVE-2005-2471

critical

Tenable Plugins

high

high

high

high

critical

high