Actu
Vigil@nce: vixie-cron, changing timestamp
February 2010 by Vigil@nce
A local attacker can use vixie-cron to reset a file modification
time.
– Severity: 1/4
– Consequences: data creation/edition
– Provenance: user shell
– Means of attack: 1 attack
– Ability of attacker: technician (2/4)
– Confidence: confirmed by the editor (5/5)
– Diffusion of the vulnerable configuration: high (3/3)
– Creation date: 24/02/2010
IMPACTED PRODUCTS
– Fedora
– Unix - plateform
DESCRIPTION OF THE VULNERABILITY
The utime() function changes the time of a file:
– actime : time of the last access
– modtime : time of the last modification
When a user edits its crontab via "crontab -e", vixie-cron creates
a temporary file in /tmp, and uses utime() to reset its access and
modification times (in order to easily detect that the file was
changed). However, these changes are done with root privileges.
A local attacker can therefore edit his crontab, and create a
symbolic link, in order to force vixie-cron to change times of a
file.
CHARACTERISTICS
– Identifiers: CVE-2010-0424, FEDORA-2010-2751, VIGILANCE-VUL-9473
– Url: http://vigilance.fr/vulnerability/vixie-cron-changing-timestamp-9473
