Proxytunnel: Format string vulnerability

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Updated November 03, 2004

1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200411-07 / Proxytunnel
Release Date November 03, 2004
Latest Revision November 03, 2004: 01
Impact normal
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
net-misc/proxytunnel < 1.2.3 >= 1.2.3 All supported architectures

Related bugreports: #69379

Synopsis

Proxytunnel is vulnerable to a format string vulnerability, potentially allowing a remote server to execute arbitrary code with the rights of the Proxytunnel process.

2.  Impact Information

Background

Proxytunnel is a program that tunnels connections to a remote server through a standard HTTPS proxy.

Description

Florian Schilhabel of the Gentoo Linux Security Audit project found a format string vulnerability in Proxytunnel. When the program is started in daemon mode (-a [port]), it improperly logs invalid proxy answers to syslog.

Impact

A malicious remote server could send specially-crafted invalid answers to exploit the format string vulnerability, potentially allowing the execution of arbitrary code on the tunnelling host with the rights of the Proxytunnel process.

3.  Resolution Information

Workaround

You can mitigate the issue by only allowing connections to trusted remote servers.

Resolution

All Proxytunnel users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-misc/proxytunnel-1.2.3"

4.  References