Public Vulnerability Reports

IBM AIX ctstrtcasd Local File Corruption Vulnerability



The ctstrtcasd program is a setuid root application, installed by
default under newer versions of IBM AIX. It is part of the Reliable
Scalable Cluster Technology (RSCT) system.  It is also installed with
multiple IBM products under Linux, including IBM Tivoli System
Automation, IBM Cluster Systems Management, IBM Hardware Management
Console, and IBM General Parallel File System.


Local exploitation of an input validation vulnerability in the
ctstrtcasd command included by default in multiple versions of IBM Corp.
AIX could allow for the corruption or creation of arbitrary files
anywhere on the system.

If a user specifies a file with the –f option, the contents of that file
will be overwritten with 65,535 bytes of application trace data. If the
file doesn't exist, it will be created. The file creation/overwrite is
done with root privileges, thus allowing an attacker to cause a denial
of service condition by damaging the file system or by filling the drive
with 65,535 byte files.


All that is required to exploit this vulnerability is a local account.
Exploitation does not require any knowledge of application internals,
making exploitation trivial, even for unskilled attackers. It
is not evident that privilege escalation is possible through abuse of


iDEFENSE has confirmed the existence of this vulnerability in IBM AIX
5.2. IBM has reported that RSCT versions and greater are
affected, for AIX 5.2 and 5.3 on pSeries; AIX on i5/OS (iSeries); RSCT
on Linux (pSeries, xSeries, zSeries), and the pSeries Hardware
Management Console. Products shipping and installing these affected
versions of RSCT as reported by IBM are as follows:
  IBM AIX 5L Version 5.2 on pSeries
  IBM AIX 5L Version 5.3 on pSeries
  IBM AIX 5L Version 5.2, 5.3 on an i5/OS (iSeries) partition
  IBM Tivoli System Automation (TSA) for Linux 1.1
  IBM Tivoli System Automation (TSA) for Multiplatforms 1.2
  IBM Cluster Systems Management (CSM) for Linux Version 1.4
     (version 1.4 and greater)
  IBM Hardware Management Console (HMC) for pSeries Version 3
  IBM Hardware Management Console (HMC) for pSeries Version 4
  IBM General Parallel File System (GPFS) Version 2 Release 2
      on Linux for xSeries and Linux for pSeries


Only allow trusted users local access to security critical systems.
Alternately, remove the setuid bit from ctstrtcasd using chmod 555


"Apply the workarounds or APARs as described [in the associated IBM
Security Alert].

If you would like to receive AIX Security Advisories via email, please


The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2004-0828 to these issues. This is a candidate for inclusion
in the CVE list (, which standardizes names for
security problems.


08/11/2004    Initial vendor notification
08/25/2004    Secondary vendor notification
08/26/2004    Vendor response
09/27/2004    Coordinated public disclosure


iDEFENSE Labs is credited with this discovery.
Get paid for vulnerability research


Copyright © 2004 Verisign, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email for permission.

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.