I. BACKGROUND
Hewlett-Packard Co.'s /sbin/passwd binary supplied with its HP UX B.10.20 operating system is an integral system process.
II. DESCRIPTION
Hewlett-Packard Co.'s /sbin/passwd binary supplied with its HP UX B.10.20 operating system contains a buffer overflow that could allow a local privilege-escalation attack.
The environment variable LANG, which is used to control the language setting of the local subsystem, causes the /sbin/passwd binary to crash when filled with a string of approximately 4,240 bytes. This allows an attacker to gain control of the return address of the executing function, and, in turn, execute arbitrary code with the privileges of the /sbin/passwd binary. This binary is installed setuid to root by default.
III. ANALYSIS
Exploitation of this vulnerabilty allows a local attacker to assume root privilieges of the target computer. As no official patch is available, apply the workaround below.
iDEFENSE has proof of concept exploit code demonstrating the impact of this vulnerability.
IV. DETECTION
iDEFENSE has verified that HPUX 10.20 is affected.
V. WORKAROUND
Remove the setuid bit on the executable with the chmod command:
chmod u-s /sbin/passwd
VI. VENDOR FIX
HP does not plan to develop a patch for this issue. HP recommends using chmod to remove the setuid bit.
VII. CVE INFORMATION
A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number CAN-2003-0061 has been assigned to this issue.
VIII. DISCLOSURE TIMELINE
| 01/11/2002 |
Exploit acquired by iDEFENSE |
| 01/20/2003 |
Initial vendor notification |
| 02/03/2003 |
iDEFENSE Clients notified |
| 02/10/2003 |
Public Disclosure |
IX. CREDIT
Euan Briggs is credited with this discovery.
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X. LEGAL NOTICES
Copyright © 2004 iDEFENSE, Inc.
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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
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,
this information.
