rssh: Format string vulnerability

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200410-28 / rssh
Release Date	October 27, 2004
Latest Revision	May 22, 2006: 02
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
app-shells/rssh	< 2.2.2	>= 2.2.2	All supported architectures

Related bugreports: #66988

Synopsis

rssh is vulnerable to a format string vulnerability that allows arbitrary execution of code with the rights of the connected user, thereby bypassing rssh restrictions.

2. Impact Information

Background

rssh is a restricted shell, allowing only a few commands like scp or sftp. It is often used as a complement to OpenSSH to provide limited access to users.

Description

Florian Schilhabel from the Gentoo Linux Security Audit Team found a format string vulnerability in rssh syslogging of failed commands.

Impact

Using a malicious command, it may be possible for a remote authenticated user to execute arbitrary code on the target machine with user rights, effectively bypassing any restriction of rssh.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All rssh users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=app-shells/rssh-2.2.2"

4. References

Page updated October 27, 2004

Summary: This is a Gentoo Linux Security Advisory

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