CVE-2000-1032 in Firewall-1
Summary
by MITRE
The client authentication interface for Check Point Firewall-1 4.0 and earlier generates different error messages for invalid usernames versus invalid passwords, which allows remote attackers to identify valid usernames on the firewall.
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Analysis
by VulDB Data Team • 10/11/2025
The vulnerability described in CVE-2000-1032 represents a classic information disclosure flaw within the Check Point Firewall-1 4.0 and earlier versions authentication mechanism. This weakness stems from the inconsistent error messaging behavior that occurs during the client authentication process, where the system provides distinct feedback for different types of authentication failures. The flaw exists in the fundamental design of the authentication interface, creating a predictable pattern that adversaries can exploit to determine which usernames are valid within the system's user base.
The technical implementation of this vulnerability demonstrates a clear violation of security by design principles, specifically targeting the principle of least information disclosure. When an attacker attempts to authenticate with the firewall system, the authentication interface responds differently based on whether the provided username is valid or invalid, even when the password is incorrect. This differential response creates a side-channel attack vector that exposes information about the system's user database structure. The vulnerability directly maps to CWE-200, which addresses information exposure through improper error handling, and represents a fundamental flaw in the authentication protocol implementation.
From an operational perspective, this vulnerability significantly weakens the security posture of organizations relying on Check Point Firewall-1 versions prior to 4.0. Attackers can systematically enumerate valid usernames through simple authentication attempts, potentially leading to more sophisticated attacks such as credential stuffing, brute force attempts, or social engineering campaigns. The exposed information about valid usernames creates a foundation for further exploitation, as it reduces the search space for attackers attempting to gain unauthorized access to the firewall system. This vulnerability aligns with ATT&CK technique T1078.004, which covers valid accounts through compromised credentials, by providing attackers with a method to identify potential targets within the system's user base.
The impact of this vulnerability extends beyond simple user enumeration, as it fundamentally undermines the security model of the authentication system. Organizations may unknowingly expose their user directory structure to potential attackers, creating opportunities for targeted attacks against legitimate users. The flaw demonstrates poor security architecture where the system's response behavior inadvertently reveals sensitive information about its internal state. The vulnerability also highlights the importance of consistent error handling in security-critical systems, where different responses for similar failures can create exploitable patterns. Effective mitigation requires implementing uniform error messaging that does not distinguish between invalid usernames and invalid passwords, ensuring that authentication failures provide no additional information to potential attackers beyond the fact that authentication was unsuccessful. This vulnerability serves as a critical reminder of the importance of thorough security testing and the need for comprehensive authentication system design that considers all potential attack vectors.