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

From: CERT Advisory (cert-advisory@cert.org)
Date: 05/06/02

Date: Mon, 6 May 2002 16:47:10 -0400 (EDT)
From: CERT Advisory <cert-advisory@cert.org>
To: cert-advisory@cert.org


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)


   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:

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:


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


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


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


     See the Sun Alert Notification available at

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

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

   This document is available from:

CERT/CC Contact Information

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   Revision History
      May 06, 2002: Initial release

Version: PGP 6.5.8