5 - USN-145-1

A security issue affects the following Ubuntu releases:

Ubuntu 4.10 (Warty Warthog) Ubuntu 5.04 (Hoary Hedgehog)

The following packages are affected:

wget

The problem can be corrected by upgrading the affected package to version 1.9.1-4ubuntu0.1 (for Ubuntu 4.10), or 1.9.1-10ubuntu2.1 (for Ubuntu 5.04). In general, a standard system upgrade is sufficient to effect the necessary changes.

Details follow:

Jan Minar discovered a path traversal vulnerability in wget. If the name ".." was a valid host name (which can be achieved with a malicious or poisoned domain name server), it was possible to trick wget into creating downloaded files into arbitrary locations with arbitrary names. For example, wget could silently overwrite the users ~/.bashrc and other configuration files which are executed automatically. (CAN-2004-1487)

Jan Minar also discovered that wget printed HTTP response strings from the server to the terminal without any filtering. Malicious HTTP servers could exploit this to send arbitrary terminal sequences and strings which would then be executed and printed to the console. This could potentially lead to arbitrary code execution with the privileges of the user invoking wget. (CAN-2004-1488)

Hugo Vázquez Caramés discovered a race condition when writing output files. After wget determined the output file name, but before the file was actually opened (the time window is determined by the delay of the first received data packet), a local attacker with with write permission to the download directory could create a symbolic link with the name of the output file. This could be exploited to overwrite arbitrary files with the permissions of the user invoking wget. (CAN-2004-2014)