The vulnerability, which was discovered by Internet Security Systems, affects a wide range of Check Point products, including a particular ASN.1 decoding library, used in creating the VPN connection. The products include versions of VPN-1, FireWall-1, Provider-1 and SSL Network Extender. Users of current product versions and customers not using Remote Access VPNs or gateway-to-gateway VPNs are not affected, Check Point said. Check Points enterprise security products are among the most widely used on the Internet.
An advisory, including ASN.1 patches, can be found on Check Points Web site.
The problem lies with Check Points implementation of the Internet Security Association and Key Management Protocol (ISAKMP), used in the Internet Key Exchange (IKE) that negotiates and exchanges keys for encrypted transport or tunneling of network traffic, according to ISS Mark Dowd and Neel Mehta, who discovered the problem. During the setup of a VPN connection, when the server attempts to decode ASN.1-encoded packets as part of the initial key exchange, an attacker can trigger an arbitrary-length heap overflow, allowing the execution of arbitrary code on the server, ISS said in its advisory.
The attacker doesnt need to be authenticated, and servers are likely to be vulnerable in the default configuration, ISS said. If a feature called Aggressive Mode IKE is switched on, attackers can compromise a system via an instant, single-packet attack; otherwise, they must initiate a real IKE negotiation, Check Point said.
Security monitoring tools cant detect the malformed packets because they are necessarily encrypted during the IKE negotiation, Check Point said. The company said its not aware that any customers have been compromised so far.
This is not the first time serious holes in Check Point products have been uncovered by ISS. In February, ISS warned of two vulnerabilities in VPN-1 and Firewall-1 products, one involving the HTTP Security Server application proxy in Firewall-1, and a second within the ISAKMP processing in VPN-1 Server, SecuRemote and SecureClient. In May, Check Point discovered another ISAKMP bug in VPN-1.
Other companies have had similar difficulty in keeping the lid on security problems within products designed to ensure security. In January, Symantec Corp. patched a bug in the LiveUpdate component of its anti-virus software that could have allowed someone with network access to bypass security into privileged areas. In February, Sophos admitted its anti-virus software could be bypassed or exploited in a denial-of-service attack. In April, Cisco Systems Inc. disclosed a number of bugs in its products, including its VPN hardware and software.