Diskcheck.pl is a PERL script, part of Red Hat's powertools suite, that alerts a system administrator if any file system approaches capacity. In creating email alerts, diskcheck.pl creates insecure temporary files in a world-writable directory, which may permit an attacker to corrupt any writable file on the system.
Diskcheck.pl is designed to run hourly. When any file system approaches capacity, it generates an email message to the system administrator, using a temporary file with a predictable name in the /tmp directory, without checking for the prior existence or ownership of this file. By its nature, Disckcheck runs with setuid root.
By creating a symbolic link with appropriate name and pointed to any writable file on the system, a local attacker can corrupt that file when diskcheck detects a file system approaching capacity.
Apply vendor patches; see the Systems Affected section below.
Modify diskcheck.pl to remove any file from /tmp named for its temporary file.
This vulnerability was first announced by Stan Bubrouski .
This document was last modified by Tim Shimeall.
|Date First Published:||2001-10-08|
|Date Last Updated:||2001-10-08 16:59 UTC|