Ubuntu Security Notice USN-127-1
17th May, 2005
bzip2 vulnerabilities
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 5.04
- Ubuntu 4.10
Details
Imran Ghory discovered a race condition in the file permission restore
code of bunzip2. While a user was decompressing a file, a local
attacker with write permissions in the directory of that file could
replace the target file with a hard link. This would cause bzip2 to
restore the file permissions to the hard link target instead of to the
bzip2 output file, which could be exploited to gain read or even write
access to files of other users. (CAN-2005-0953)
Specially crafted bzip2 archives caused an infinite loop in the
decompressor which resulted in an indefinitively large output file
("decompression bomb"). This could be exploited to a Denial of Service
attack due to disk space exhaustion on systems which automatically
process user supplied bzip2 compressed files. (CAN-2005-1260)
Update instructions
The problem can be corrected by updating your system to the following package version:
- Ubuntu 5.04:
- bzip2
- libbz2-1.0
- Ubuntu 4.10:
- bzip2
- libbz2-1.0
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
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