Ubuntu 4.10 / 5.04 : wget vulnerabilities (USN-145-1)
Medium Nessus Plugin ID 20538
SynopsisThe remote Ubuntu host is missing a security-related patch.
DescriptionJan 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 Vazquez Carames 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.
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected wget package.