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AUSCERT External Security Bulletin Redistribution
ESB-2004.0798 -- iDEFENSE Security Advisory 12.20.04
IBM AIX invscout Local Command Execution Vulnerability
21 December 2004
AusCERT Security Bulletin Summary
Operating System: AIX
Impact: Execute Arbitrary Code/Commands
Access: Existing Account
CVE Names: CAN-2004-1054
Original Bulletin: http://www.idefense.com/application/poi/display?id=171
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IBM AIX invscout Local Command Execution Vulnerability
iDEFENSE Security Advisory 12.20.04
December 20, 2004
The invscout program is a setuid root application, installed by default
under newer versions of IBM AIX, that surveys the host system for
currently installed microcode or Vital Product Data (VPD).
Local exploitation of an untrusted path vulnerability in the invscout
command included by default in multiple versions of IBM Corp.'s AIX
could allow attackers to execute arbitrary code as the root user.
During execution, invscout invokes an external application ("lsvpd")
without dropping privileges. This application in turn invokes another
external application ("uname"), while trusting the user-specified PATH
environment variable. As root privileges are not dropped before this
sequence of execution occurs, it is possible for an attacker to gain
root access by specifying a controlled path and creating a malicious
binary within that path. To exploit the vulnerability, an attacker needs
only to create an executable file called "uname" that contains malicious
code, set the PATH variable to the current directory and execute
Exploitation of this vulnerability allows local attackers to gain
increased privileges. Successful explication requires a local account
and a writable directory. This directory can be the user's home
directory, or even the /tmp directory. Exploitation does not require
any knowledge of application internals, making privilege escalation
trivial, even for unskilled attackers.
iDEFENSE has confirmed the existence of this vulnerability in IBM AIX
Only allow trusted users local access to security critical systems.
Alternately, remove the setuid bit from invscout using chmod u-s
VI. VENDOR RESPONSE
"IBM provides the following fixes:
APAR number for AIX 5.1.0: IY64852 (available)
APAR number for AIX 5.2.0: IY64976 (available)
APAR number for AIX 5.3.0: IY64820 (available)
NOTE: Affected customers are urged to upgrade to 5.1.0, 5.2.0 or 5.3.0
at the latest maintenance level."
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2004-1054 to this issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
VIII. DISCLOSURE TIMELINE
11/12/2004 Initial vendor notification
11/18/2004 Initial vendor response
12/20/2004 Coordinated public disclosure
iDEFENSE Labs is credited with this discovery.
Get paid for vulnerability research
X. LEGAL NOTICES
Copyright (c) 2004 iDEFENSE, Inc.
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of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
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