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Gentoo Linux Security Advisory GLSA 200412-01
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http://security.gentoo.org/
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Severity: Normal
Title: rssh, scponly: Unrestricted command execution
Date: December 03, 2004
Bugs: #72815, #72816
ID: 200412-01
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Synopsis
========
rssh and scponly do not filter command-line options that can be
exploited to execute any command, thereby allowing a remote user to
completely bypass the restricted shell.
Background
==========
rssh and scponly are two restricted shells, allowing only a few
predefined commands. They are often used as a complement to OpenSSH to
provide access to remote users without providing any remote execution
privileges.
Affected packages
=================
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Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 net-misc/scponly < 4.0 >= 4.0
2 app-shells/rssh <= 2.2.2 Vulnerable!
-------------------------------------------------------------------
NOTE: Certain packages are still vulnerable. Users should migrate
to another package if one is available or wait for the
existing packages to be marked stable by their
architecture maintainers.
-------------------------------------------------------------------
2 affected packages on all of their supported architectures.
-------------------------------------------------------------------
Description
===========
Jason Wies discovered that when receiving an authorized command from an
authorized user, rssh and scponly do not filter command-line options
that can be used to execute any command on the target host.
Impact
======
Using a malicious command, it is possible for a remote authenticated
user to execute any command (or upload and execute any file) on the
target machine with user rights, effectively bypassing any restriction
of scponly or rssh.
Workaround
==========
There is no known workaround at this time.
Resolution
==========
All scponly users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/scponly-4.0"
Currently, there is no released version of rssh that contains a fix for
these issues. The author declared that he cannot provide a fixed
version at this time. Therefore, the rssh package has been hard-masked
prior to complete removal from Portage, and current users are advised
to unmerge the package.
References
==========
[ 1 ] BugTraq Posting
http://www.securityfocus.com/archive/1/383046/2004-11-30/2004-12-06/0
Availability
============
This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
http://security.gentoo.org/glsa/glsa-200412-01.xml
Concerns?
=========
Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@xxxxxxxxxx or alternatively, you may file a bug at
http://bugs.gentoo.org.
License
=======
Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).
The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.
http://creativecommons.org/licenses/by-sa/2.0
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