BugTraq
LimeWire Gnutella client two vulnerabilities Mar 15 2005 01:12AM
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.

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