NSFOCUS Security Advisory (SA2006-03)
IBM AIX rm_mlcache_file Local Race Condition Vulnerability
Release Date: 2006-04-24
CVE ID: CVE-2006-1247
http://www.nsfocus.com/english/homepage/research/0603.htm
Affected systems & software
===================
IBM AIX 5.1
IBM AIX 5.2
IBM AIX 5.3
Unaffected systems & software
===================
Summary
=========
NSFocus Security Team discovered a local race condition in IBM AIX
rm_mlcache_file
which could allow a local user to overwrite arbitrary file.
Description
============
rm_mlcache_file shipped with IBM AIX is used to delete some cached files.
By default it is set with suid root bit.
rm_mlcache_file contains a race condition when processing temporary files which
allows a local attacker to overwrite arbitrary files. Attackers can launch
attacks by running the program directly, or waiting till root user runs it.
Successful exploitation may result in data loss or DoS, specifically depending
on the overwritten file.
Workaround
=============
Remove the execution bit from rm_mlcache_file temporarily:
# chmod 000 /usr/bin/rm_mlcache_file
Vendor Status
==============
The vendor has released the following APAR patches to fix the vulnerability:
APAR number for AIX 5.1.0: IY82866
APAR number for AIX 5.2.0: IY82285
APAR number for AIX 5.3.0: IY82357
AIX 5 APAR patch can be downloaded at:
http://www.ibm.com/servers/eserver/support/unixservers/aixfixes.html
The temporary patch for the vulnerability can be downloaded at:
ftp://aix.software.ibm.com/aix/efixes/security/rm_mlcache_file_ifix.tar.Z
Additional Information
========================
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-1247 to this issue. This is a candidate for inclusion in the
CVE list (http://cve.mitre.org), which standardizes names for security problems.
Candidates may change significantly before they become official CVE entries.
Acknowledgment
===============
Yang Jilong of NSFocus Security Team found the vulnerability.
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==========
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NSFOCUS Security Team <security@xxxxxxxxxxx>
NSFOCUS INFORMATION TECHNOLOGY CO.,LTD
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