Vulnerability Note VU#530057

Cisco ASA fails to properly process DHCP relay packets

Original Release date: 02 May 2007 | Last revised: 03 May 2007


The Cisco Adaptive Security Appliance contains a memory exhaustion vulnerability that may occur when the DHCP service relay is enabled.


The Cisco Adaptive Security Appliance (ASA) is firewall that includes routing and intrusion prevention system (IPS) features. DHCP relay allows network devices to forward DHCP broadcast packets from a network segment that does not have a DHCP server to one that does. The Cisco ASA supports DHCP relay.

The Cisco ASA DHCP relay service contains a memory exhaustion vulnerability. An attacker may trigger the vulnerability by sending a large number of DHCP requests to a vulnerable system.


An unauthenticated attacker may be able to create a denial-of-service condition.


Cisco has released an update to address this issue. See Cisco BUG ID: CSCsh50277 for more details.

Increase DHCP lease times

Increasing the DHCP lease times may lengthen the amount of time required for an attacker to exhaust the available memory on a vulnerable system.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Cisco Systems, Inc.Affected-03 May 2007
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



This vulnerability was discovered by Lisa Sittler and Grant Deffenbaugh of CERT/CC.

This document was written by Ryan Giobbi.

Other Information

  • CVE IDs: Unknown
  • Date Public: 02 May 2007
  • Date First Published: 02 May 2007
  • Date Last Updated: 03 May 2007
  • Severity Metric: 0.64
  • Document Revision: 27


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