[ GLSA 200412-01 ] rssh, scponly: Unrestricted command execution

[GLSA]

Gentoo Linux Security Advisory

Title: rssh, scponly: Unrestricted command execution (GLSA 200412-01)
Severity: normal
Exploitable: remote
Date: December 03, 2004
Updated: May 22, 2006
Bug(s): #72815, #72816
ID: 200412-01

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

Package: net-misc/scponly
Vulnerable: < 4.0
Unaffected: >= 4.0
Architectures: All supported architectures

Package: app-shells/rssh
Vulnerable: <= 2.2.2
Unaffected: >= 2.2.3
Architectures: All 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: