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Gentoo Linux Security Advisory                           GLSA 200512-17
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                                            http://security.gentoo.org/
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  Severity: High
     Title: scponly: Multiple privilege escalation issues
      Date: December 29, 2005
      Bugs: #116526
        ID: 200512-17

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Synopsis
========

Local users can exploit an scponly flaw to gain root privileges, and
scponly restricted users can use another vulnerability to evade shell
restrictions.

Background
==========

scponly is a restricted shell, allowing only a few predefined commands.
It is often used as a complement to OpenSSH to provide access to remote
users without providing any remote execution privileges.

Affected packages
=================

    -------------------------------------------------------------------
     Package           /  Vulnerable  /                     Unaffected
    -------------------------------------------------------------------
  1  net-misc/scponly        < 4.2                              >= 4.2

Description
===========

Max Vozeler discovered that the scponlyc command allows users to chroot
into arbitrary directories. Furthermore, Pekka Pessi reported that
scponly insufficiently validates command-line parameters to a scp or
rsync command.

Impact
======

A local attacker could gain root privileges by chrooting into arbitrary
directories containing hardlinks to setuid programs. A remote scponly
user could also send malicious parameters to a scp or rsync command
that would allow to escape the shell restrictions and execute arbitrary
programs.

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-4.2"

References
==========

  [ 1 ] scponly release notes
        http://sublimation.org/scponly/index.html#relnotes

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200512-17.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@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2005 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