Advisory CA-2002-11 Heap Overflow in Cachefs Daemon (cachefsd)

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CERT Advisory CA-2002-11 Heap Overflow in Cachefs Daemon (cachefsd)

Original release date: May 06, 2002
Last revised:
Source: CERT/CC

A complete revision history can be found at the end of this file.

Systems Affected

 * Sun Solaris 2.5.1, 2.6, 7, and 8 (SPARC and Intel Architectures)

Overview

Sun's NFS/RPC file system cachefs daemon (cachefsd) is shipped and
installed by default with Sun Solaris 2.5.1, 2.6, 7, and 8 (SPARC and
Intel architectures). A remotely exploitable vulnerability exists in
cachefsd that could permit a remote attacker to execute arbitrary code
with the privileges of the cachefsd, typically root. The CERT/CC has
received credible reports of scanning and exploitation of Solaris
systems running cachefsd.

I. Description

A remotely exploitable heap overflow exists in the cachefsd program
shipped and installed by default with Sun Solaris 2.5.1, 2.6, 7, and 8
(SPARC and Intel architectures). Cachefsd caches requests for
operations on remote file systems mounted via the use of NFS protocol.
A remote attacker can send a crafted RPC request to the cachefsd
program to exploit the vulnerability.

Logs of exploitation attempts may resemble the following:

May 16 22:46:08 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Segmentation Fault - core dumped

May 16 22:46:21 victim-host last message repeated 7 times

May 16 22:46:22 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Bus Error- core dumped

May 16 22:46:24 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Segmentation Fault - core dumped

May 16 22:46:56 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Bus Error - core dumped

May 16 22:46:59 victim-host last message repeated 1 time

May 16 22:47:02 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Segmentation Fault - core dumped

May 16 22:47:07 victim-host last message repeated 3 times

May 16 22:47:09 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Hangup

May 16 22:47:11 victim-host inetd[600]: /usr/lib/fs/cachefs/cachefsd:
Segmentation Fault - core dumped

According a Sun Alert Notification, failed attempts to exploit this
vulnerability may leave a core dump file in the root directory. The
presence of the core file does not preclude the success of subsequent
attacks. Additionally, if the file /etc/cachefstab exists, it may
contain unusual entries.

This issue is also being referenced as CAN-2002-0085:

 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0085

The Australian Computer Emergency Response Team has also issued an
advisory related to incident activity exploiting cachefsd:

http://www.auscert.org.au/Information/Advisories/advisory/AA-2002.01.txt

II. Impact

A remote attacker may be able to execute code with the privileges of
the cachefsd process, typically root.

III. Solution

Apply a patch from your vendor

Appendix A contains information provided by vendors for this advisory.

If a patch is not available, disable cachefsd in inetd.conf until a
patch can be applied.

If disabling the cachefsd is not an option, follow the suggested
workaround in the Sun Alert Notification.

Appendix A. - Vendor Information

This appendix contains information provided by vendors for this
advisory. As vendors report new information to the CERT/CC, we will
update this section and note the changes in our revision history. If a
particular vendor is not listed below, please check the Vulnerability
Note (VU#635811) or contact your vendor directly.

IBM

 IBM's AIX operating system, all versions, is not vulnerable.

SGI

 SGI does not ship with SUN cachefsd, so IRIX is not vulnerable.

Sun

 See     the     Sun     Alert     Notification     available     at
 http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsalert%2F44309.

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The CERT/CC acknowledges the eSecurity Online Team for discovering and
reporting on this vulnerability and thanks Sun Microsystems for their
technical assistance.

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Feedback can be directed to the authors:
Jason A. Rafail and Jeffrey S. Havrilla

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This document is available from:
http://www.cert.org/advisories/CA-2002-11.html

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Phone: +1 412-268-7090 (24-hour hotline)
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Revision History
May 06, 2002: Initial release

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