CVE-2000-0808 in Firewall-1
Summary
by MITRE
The seed generation mechanism in the inter-module S/Key authentication mechanism in Check Point VPN-1/FireWall-1 4.1 and earlier allows remote attackers to bypass authentication via a brute force attack, aka "One-time (s/key) Password Authentication."
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Analysis
by VulDB Data Team • 05/09/2019
The vulnerability described in CVE-2000-0808 targets the S/Key authentication mechanism implemented within Check Point VPN-1/FireWall-1 versions 4.1 and earlier, representing a critical weakness in the cryptographic seed generation process that fundamentally undermines the security of one-time password authentication. This flaw resides in the inter-module communication framework where the seed values used for generating sequential one-time passwords are improperly managed, creating a predictable pattern that adversaries can exploit through brute force techniques.
The technical implementation of this vulnerability stems from insufficient randomness in the seed generation algorithm used by the S/Key module, which operates under the principle of generating sequential one-time passwords based on a shared secret and a counter value. When the seed generation mechanism fails to produce sufficiently random values, it creates a vulnerability that allows attackers to predict future password values or reverse-engineer the seed through systematic brute force attempts. This weakness directly violates the fundamental security requirements for time-based one-time password systems as defined in various cryptographic standards and best practices.
The operational impact of this vulnerability extends beyond simple authentication bypass to potentially compromise entire network security infrastructures, as the S/Key mechanism serves as a critical authentication layer for VPN connections and firewall access controls. Attackers leveraging this vulnerability can gain unauthorized access to protected networks without requiring knowledge of legitimate user credentials, effectively neutralizing the security benefits that one-time passwords are designed to provide. The attack vector is particularly dangerous because it requires no special privileges or access to the target system, making it accessible to any remote attacker who can observe the authentication process.
Security practitioners should recognize this vulnerability as a classic example of poor random number generation practices that aligns with CWE-330, which specifically addresses the use of insufficiently random values in security functions. The attack pattern follows established methodologies documented in MITRE ATT&CK framework under the credential access category, where adversaries exploit weaknesses in authentication mechanisms to obtain unauthorized access. Organizations using affected Check Point products should immediately implement mitigations including upgrading to patched versions, implementing additional authentication layers, and monitoring for suspicious authentication patterns that may indicate exploitation attempts. The vulnerability also highlights the importance of proper cryptographic implementation and the necessity of thorough security testing of authentication mechanisms before deployment in production environments.