NSFOCUS Security Advisory (SA2006-02)

IBM AIX mklvcopy Local Privilege Escalation Vulnerability 

Release Date: 2006-04-24

CVE ID: CVE-2006-1246

http://www.nsfocus.com/english/homepage/research/0602.htm

Affected systems & software
===================
IBM AIX 5.3

Unaffected systems & software
===================

Summary
=========

NSFocus Security Team discovered a local privilege escalation vulnerability 
in IBM AIX mklvcopy which allows users of local system group to gain root 
privilege.

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

The mklvcopy shipped with IBM AIX 5.3 is used to increase the number of copies 
in each logical partition in LogicalVolume. By default mklvcopy is set with 
suid root bit, and can be run by system group users.

mklvcopy contains a vulnerability when calling external commands, which allows 
a local attacker to execute arbitrary command as root. Successful exploitation 
requires the attacker should gain system group privilege first. 

Workaround
=============

Remove suid root bit from mklvocpy.

    # chmod a-s /usr/sbin/mklvcopy
    
Vendor Status
==============

The vendor has released Patch APAR IY82739 to fix the vulnerability. The related 
link is:
http://www-1.ibm.com/support/docview.wss?uid=isg1IY82739

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/mklvcopy_ifix.tar.Z

Additional Information
========================

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2006-1246 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@nsfocus.com>
NSFOCUS INFORMATION TECHNOLOGY CO.,LTD
(http://www.nsfocus.com)

PGP Key: http://www.nsfocus.com/homepage/research/pgpkey.asc
Key fingerprint = F8F2 F5D1 EF74 E08C 02FE 1B90 D7BF 7877 C6A6 F6DA