Gentoo: NASM Buffer overflow vulnerability
Posted by Joe Shakespeare   
Gentoo NASM is vulnerable to a buffer overflow that allows an attacker to execute arbitrary code through the use of a malicious object file.

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Gentoo Linux Security Advisory                           GLSA 200412-20
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: NASM: Buffer overflow vulnerability
      Date: December 20, 2004
      Bugs: #74477
        ID: 200412-20

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Synopsis
========

NASM is vulnerable to a buffer overflow that allows an attacker to
execute arbitrary code through the use of a malicious object file.

Background
==========

NASM is a 80x86 assembler that has been created for portability and
modularity. NASM supports Pentium, P6, SSE MMX, and 3DNow extensions.
It also supports a wide range of objects formats (ELF, a.out, COFF,
...), and has its own disassembler.

Affected packages
=================

    -------------------------------------------------------------------
     Package        /  Vulnerable  /                        Unaffected
    -------------------------------------------------------------------
  1  dev-lang/nasm     <= 0.98.38                        >= 0.98.38-r1

Description
===========

Jonathan Rockway discovered that NASM-0.98.38 has an unprotected
vsprintf() to an array in preproc.c. This code vulnerability may lead
to a buffer overflow and potential execution of arbitrary code.

Impact
======

A remote attacker could craft a malicious object file which, when
supplied in NASM, would result in the execution of arbitrary code with
the rights of the user running NASM.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All NASM users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=dev-lang/nasm-0.98.38-r1"

References
==========

  [ 1 ] Original Advisory
        http://sourceforge.net/mailarchive/forum.php?thread_id=6166881&forum_id=4978

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200412-20.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.0