Vulnerability Note VU#740619

SSH Secure Shell for Servers fails to remove child process from master process group

Overview

A locally exploitable privilege escalation vulnerability exists in SSH Secure Shell versions 2.0.13 - 3.2.1.

I. Description

Secure Shell for Servers, developed by SSH Communications Security, does not properly remove the child process from the master process group after non-interactive command execution. Quoting from the SSH Communications Security Advisory:

When used in non-interactive connections, a defect in process grouping
of SSH Secure Shell processes may allow malicious activity. If
executing a command without a pty (including running commands and
subsystems) the child process remains in the process group of the
master process.

On platforms relying on getlogin() (mainly the different BSD variants)
malicious users can at least send misleading messages to syslog and
others applications (getlogin() call will return "root").

For more details, please see the SSH Communications Security Advisory.

II. Impact

A local attacker may be able to gain elevated privileges.

III. Solution

Upgrade your software. Note that both Secure Shell for Servers and Secure Shell for Workstations need to be updated to eliminate this vulnerability.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Hewlett-Packard Company	Not Vulnerable	29-May-2008
SSH Communications Security	Vulnerable	14-May-2003

References

http://www.ssh.com/company/newsroom/article/286/

Credit

Thanks to Logan Gabriel for reporting this vulnerability.

This document was written by Ian A Finlay.

Other Information

Date Public:	2002-11-25
Date First Published:	2002-11-25
Date Last Updated:	2008-05-29
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Metric:	8.35
Document Revision:	15

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