Vigil@nce: CUPS, denial of service via add-rss-subscription
November 2008 by Vigil@nce
An attacker can use the add-rss-subscription feature of CUPS in order to stop it.
Consequences: denial of service of service
Means of attack: 1 attack
Ability of attacker: technician (2/4)
Confidence: unique source (2/5)
Diffusion of the vulnerable configuration: high (3/3)
Creation date: 19/11/2008
Unix - plateform
The cgi-bin/admin script of CUPS implements several operations:
start-printer : start the printer
set-printer-options : change its options
add-rss-subscription : subscribe to a RSS feed reporting log events
When the "add-rss-subscription" feature is called more than 100 (MaxSubscriptions) times, a NULL pointer is dereferenced and stops CUPS.
To setup this attack, the attacker can create a HTML page containing 101 urls pointing to the feed to subscribe, and then invite the victim to display this HTML page.
An attacker can therefore create a malicious HTML page and invite the victim to read it in order to stop CUPS.