Public Vulnerability Reports

SCO Openserver authsh 'Home' Buffer Overflow Vulnerability



SCO OpenServer is a UNIX-like operating system for x86 platforms.


Local exploitation of a buffer overflow vulnerability in The SCO Group
Inc.'s Openserver operating system could allow an attacker to gain root

The authsh utility is a standard binary distributed with the Openserver
platform. The vulnerability specifically exists because of a lack of
bounds checking on the value given to the "HOME" environment variable.
Local attackers can supply a specially crafted string to overflow a
stack buffer and execute arbitrary code with group auth privileges.


Successful exploitation of this vulnerability will result in execution
of arbitrary code with permissions of the running process. The binary is
setgid auth by default and can be used by attackers with a local account
to gain root privileges, as the group auth has write access to system
authentication information. An attacker would only need to modify the
system passwd file to grant an account they control superuser


iDEFENSE has confirmed the existence of this vulnerability in SCO
Openserver 5.0.7. It is suspected that earlier versions are also


As a workaround solution, remove the setgid bit from the authsh binary
until a vendor patch can be applied.

  # chmod -g /opt/K/SCO/Unix/5.0.7Hw/usr/lib/sysadm/authsh


The vendor has released the following advisory for this issue:


The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2005-2926 to this issue. This is a candidate for inclusion in
the CVE list (, which standardizes names for
security problems.


09/08/2005   Initial vendor notification
09/09/2005   Initial vendor response
10/24/2005   Public disclosure


iDEFENSE Labs is credited with the discovery of this vulnerability.

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Copyright © 2005 Verisign, Inc.

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