Rule: -- Sid: 3046 -- Summary: This event is generated when an attempt is made to exploit a known vulnerability in Ethereal. -- Impact: Serious. Denial of Service (DoS). -- Detailed Information: Ethereal is a multi-platform network protocol analyser capable of displaying network data to the user in a graphical user interface. An error in the processing of access control lists (ACLs) concerning the size of the access control entries (ACEs) may lead to a Denial of Service (DoS) condition in Ethereal. The ACL parsing routine trusts the size of the ACE given in the packet during processing. If a sufficiently large ACL structure is supplied combined with a specified ACE size of 0, it is possible to cause the DoS condition to occur. -- Affected Systems: Ethereal 0.10.7 and prior -- Attack Scenarios: An attacker needs to craft packet data containing large NT ACLs, the attacker then needs to specify one of the ACEs as having a size of 0. -- Ease of Attack: Moderate. -- False Positives: None Known -- False Negatives: None Known -- Corrective Action: Apply the appropriate vendor supplied patch Upgrade to the latest non-affected version of the software. -- Contributors: Sourcefire Research Team Brian Caswell Nigel Houghton -- Additional References: --