CVE-2000-1037 in Firewall-1
Summary
by MITRE
Check Point Firewall-1 session agent 3.0 through 4.1 generates different error messages for invalid user names versus invalid passwords, which allows remote attackers to determine valid usernames and guess a password via a brute force attack.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability described in CVE-2000-1037 represents a classic information disclosure issue within Check Point Firewall-1 session agent versions 3.0 through 4.1. This flaw stems from the application's inconsistent error handling behavior when processing authentication attempts. The security implications arise from the system's ability to differentiate between invalid usernames and invalid passwords through distinct error messages, creating a reconnaissance opportunity for malicious actors. This type of vulnerability falls under the category of information exposure, specifically categorized as CWE-209 in the Common Weakness Enumeration framework, which deals with the exposure of error messages that reveal system information. The issue demonstrates poor security design principles where the system's response to authentication failures inadvertently provides attackers with actionable intelligence about the target environment.
The technical flaw manifests in the session agent's authentication mechanism where it returns different error codes or messages depending on whether the authentication failure stems from a non-existent username or an incorrect password. This differential response creates a side-channel attack vector that can be exploited through automated tools to enumerate valid usernames within the system. Attackers can systematically test various username combinations and observe the different error responses to identify which accounts exist within the system. The vulnerability essentially transforms a simple authentication process into a username enumeration mechanism, where the system's own error handling becomes a security weakness rather than a protective feature. This behavior directly violates the principle of least information disclosure, which is a fundamental security design principle that recommends providing minimal information in error messages to prevent attackers from gaining insights into the system's internal state.
The operational impact of this vulnerability extends beyond simple credential guessing, as it enables attackers to conduct more sophisticated brute force attacks with significantly higher success rates. Once valid usernames are identified, attackers can focus their password guessing efforts on specific accounts rather than attempting to guess across all possible user accounts. This targeted approach dramatically reduces the time and computational resources required to compromise accounts, making the attack more efficient and effective. The vulnerability also creates opportunities for account lockout attacks where attackers can systematically test usernames to identify valid accounts and then attempt to lock out legitimate users through repeated failed authentication attempts. From an attacker's perspective, this vulnerability represents a critical weakness that transforms a complex multi-step attack into a more straightforward enumeration followed by targeted password guessing. The impact is particularly severe in environments where the session agent serves as a critical authentication point for network access control.
Mitigation strategies for this vulnerability should focus on implementing consistent error handling across all authentication attempts regardless of the underlying cause of failure. Security practitioners should ensure that all authentication failures return identical error messages to prevent information leakage about account validity. This approach aligns with the security principle of providing generic error responses that do not reveal specific details about authentication failures. Organizations should also implement account lockout mechanisms with intelligent throttling to prevent brute force attacks from succeeding even if username enumeration is possible. Additionally, the deployment of intrusion detection systems that monitor for authentication pattern anomalies can provide early warning of potential exploitation attempts. The implementation of multi-factor authentication and strong password policies serves as an additional layer of defense against successful exploitation. This vulnerability highlights the importance of security testing that includes examining error handling behavior, particularly in authentication systems where inconsistent responses can create exploitable information leakage channels. The remediation process should involve thorough code review of authentication modules to ensure that error handling is standardized and that no information is revealed that could aid attackers in their reconnaissance efforts.