Tripwire is a file integrity verification utility for Unix and Linux operating systems. In some implementations, tripwire opens insecure temporary files with predictable names in publically-writable directories. Using a symbolic link attack, a local intruder may overwrite or create arbitrary files on machines running tripwire.
Tripwire opens temporary files in /tmp using predictable names without first checking for prior existence or ownership of these files. The files are opened when building or updating tripwire's database of file checksums.
By creating symbolic links with appropriate names within a very tight time window, a local attacker may be able to redirect the data sent to the temporary file to arbitrary files on machines running tripwire. Since tripwire normally is executed by the system administrator, file protections will not apply. The file overwrite may result in disabling of system services, crashing the machine, or disabling of system protections.
Apply vendor patches; see the Systems Affected section below.
Clear /tmp prior to execution of tripwire.
This vulnerability was first discovered by Jamo Huuskonen.
This document was last modified by Tim Shimeall.
|Date First Published:||2001-11-15|
|Date Last Updated:||2001-11-15 16:25 UTC|