MLDonkey: Privilege escalation

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200710-25 / mldonkey
Release Date	October 24, 2007
Latest Revision	November 07, 2007: 02
Impact	high
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-p2p/mldonkey	< 2.9.0-r3	>= 2.9.0-r3	All supported architectures

Related bugreports: #189412

Synopsis

The Gentoo MLDonkey ebuild adds a user to the system with a valid login shell and no password.

2. Impact Information

Background

MLDonkey is a peer-to-peer filesharing client that connects to several different peer-to-peer networks, including Overnet and BitTorrent.

Description

The Gentoo MLDonkey ebuild adds a user to the system named "p2p" so that the MLDonkey service can run under a user with low privileges. With older Portage versions this user is created with a valid login shell and no password.

Impact

A remote attacker could log into a vulnerable system as the p2p user. This would require an installed login service that permitted empty passwords, such as SSH configured with the "PermitEmptyPasswords yes" option, a local login console, or a telnet server.

3. Resolution Information

Workaround

See Resolution.

Resolution

Change the p2p user's shell to disallow login. For example, as root run the following command:

Code Listing 3.1: Resolution

# usermod -s /bin/false p2p

NOTE: updating to the current MLDonkey ebuild will not remove this vulnerability, it must be fixed manually. The updated ebuild is to prevent this problem from occurring in the future.

4. References

CVE-2007-5714

Page updated October 24, 2007

Summary: This is a Gentoo Linux Security Advisory

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