Public Vulnerability Reports

Hewlett Packard HP-UX ftpd Remote Buffer Overflow Vulnerability

12.21.04

BACKGROUND

HP-UX FTP Daemon is a service included in HP-UX that implements the File
Transfer Protocol.

DESCRIPTION

Remote exploitation of a buffer overflow vulnerability in the file
transfer protocol (FTP) daemon included in multiple versions of Hewlett-
Packard Development Co.'s (HP) HP-UX allows attackers to gain remote
root access in certain configurations.

The problem specifically exists when the FTP daemon is configured via
/etc/inetd.conf to log debug information using –v switch. This is a not
a default configuration option. When parsing a long command request, an
exploitable stack overflow will occur. The overflow occurs before
authentication, thus eliminating the need for a local or anonymous FTP
account.

ANALYSIS

Exploitation of this vulnerability allows unauthenticated remote
attackers to execute arbitrary code under the privileges of the FTP
daemon server, usually root. The severity of this issue is mitigated by
the fact that in most production environments, administrators will not
be using the debug-logging feature of FTP daemon.

DETECTION

iDEFENSE has confirmed the existence of this vulnerability in HP-UX
11.11i. It is suspected that previous versions are also vulnerable.

To determine if a specific configuration is vulnerable, check
/etc/inetd.conf for the ftpd line and see if the debug switch is
enabled:

grep 'ftpd' /etc/inetd.conf | grep -- -v 

If the above command returns text, then the FTP daemon is running in
debug mode.

WORKAROUND

Do not use the –v flag in the FTP daemon entry line in /etc/inetd.conf.
If debug-logging is necessary, consider allowing only trusted hosts
access to the service using firewall rules or TCP wrappers.

VENDOR RESPONSE

This vulnerability was addressed in the following patches:

HP-UX B.11.00: PHNE_29460
HP-UX B.11.04: PHNE_31034
HP-UX B.11.11: PHNE_29461
HP-UX B.11.22: PHNE_29462

CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

DISCLOSURE TIMELINE

12/02/2004   Initial vendor notification
12/03/2004   Initial vendor response
12/21/2004   Public disclosure

CREDIT

iDEFENSE Labs is credited with this discovery.

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LEGAL NOTICES

Copyright © 2004 Verisign, 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
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