LimeWire Gnutella client two vulnerabilities

[Kevin Walsh <kwalsh () cs cornell edu>]

Summary:
Recent versions of the LimeWire client contain vulnerabilities that allow a remote user access to many or all files on 
a users machine. LimeWire is a popular client for the Gnutella filesharing network.

Vulnerability 1 - Inappropriate Handling of "resource get" requests.

Symptom:A remote attacker can request and read any file on a host running an affected version of LimeWire. Gnutella 
"push style" requests also vulnerable under most conditions, and therefore a local firewall does not prevent the 
attack. The files accessible to a remote attacker include all of the user's private, local files, and any file on the 
machine if the user has administrator privileges, a common scenario in Windows.

Versions affected: LimeWire versions 4.1.2 - 4.5.6, inclusive. 

Details: The handling of "resource get" requests is the immediate cause of the problem. A request of the form 
"/gnutella/res/[filename]" returns the named file. For example, one can telnet to a LimeWire client using the default 
LimeWire port and type the following text: 

GET /gnutella/res/C:\Windows\win.ini HTTP/1.1
User-Agent: I-AM-AN-ATTACKER/1.0
Host: 0.0.0.0:0
Accept: */*
Connection: Keep-Alive


The result is that the LimeWire client reads the file "C:\Windows\win.ini" and sends it over the network. Similarly, 
the attacker may request "/gnutella/res//etc/passwd" on Linux or unix-based machines. This attack has been tested and 
confirmed on Linux and Windows 2000 platforms. 

Remedies: This problem has been fixed in the recently released LimeWire versions 4.6.0 and later, which were released 
promptly by Lime Wire LLC after we informed them of the vulnerability. 

Vulnerability 02 - Inappropriate Handling of "magnet" requests.

Symptom:A remote attacker can request and read any file on a host running an affected version of LimeWire. The attacker 
need only be able to connect to the LimeWire client "magnet" TCP port (default port, or a port chosen from a modest 
range if default is not available). Gnutella "push style" requests are not vulnerable, so a firewall that blocks access 
to the magnet port blocks the attack. The files accessible to a remote attacker include all of the user's private, 
local files, and any file on the machine if the user has administrator privileges. 

Versions affected: LimeWire versions 3.9.6 - 4.6.0, inclusive. 

Details: Details: The handling of "magnet" requests is the immediate cause of the problem. A request of the form 
"/magnet10/[rel-filename]" returns the named file, relative to the "root" subdirectory of the LimeWire installation, 
regardless of if it is in the "root" directory, or indeed even part of the Limewire package. For example, one can 
telnet to a LimeWire client and issue an HTTP request 
“GET /magnet10/../../../../../Windows/Win.ini?Simple-test”

This example assumes that LimeWire is installed in its default installation directory. The result is that the LimeWire 
client reads the file "C:\Windows\win.ini" and sends it over the network. Similarly attacks work on Linux or unix-based 
machines. The attack has been tested and confirmed on Linux and Windows 2000 platforms, using several versions of 
LimeWire. 

Remedies: This problem has been fixed in the recently released LimeWire versions 4.8.0 and later, which were released 
promptly by Lime Wire LLC after we informed them of the vulnerability.