Risk: Medium
The NISCC (National Infrastructure Security Co-ordination Centre), a UK-sponsored inter-departmental agency, has identified nearly five thousand potential ISAKMP vulnerabilities. Tests for these vulnerabilities were created by the NISCC and distributed to an unspecified number of vendors.
While testing their products against these vulnerabilities, security firm Symantec uncovered a buffer overflow flaw in two out of the five thousand tests that can lead to a denial of service of the dynamic VPN services.
The affected products include Symantec Enterprise Firewall v8 for both Windows and Solaris, Symantec Gateway Security, Symantec Firewall /VPN Appliance, and Symantec Gateway Security. For full details on the versions and platforms, please refer to the vendor’s website referenced below. Product unaffected: Symantec Clientless VPN Gateway model 4400 v5.
Details:
Dynamic IPsec VPN tunnels require the use of ISAKMP (Internet Security Association and Key Management Protocol), a standard protocol that provides the framework for establishing, negotiating, modifying, and deleting security associations. The ISAKMP service listens on UDP port 500 on all the affected security gateways. Under certain conditions a malformed ISAKMP packet can potentially cause the ISAKMP service to crash, therefore affecting the ability and stability of dynamic VPN tunnels.
For the main article on the joint advisory released by CERT-FN and NISCC, please refer to the article below titled: ISAKMP advisory.