CVE-2000-0582 in Firewall-1
Summary
by MITRE
Check Point FireWall-1 4.0 and 4.1 allows remote attackers to cause a denial of service by sending a stream of invalid commands (such as binary zeros) to the SMTP Security Server proxy.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2000-0582 represents a critical denial of service weakness in Check Point FireWall-1 versions 4.0 and 4.1, specifically affecting the SMTP Security Server proxy component. This issue stems from inadequate input validation mechanisms within the email security proxy that processes incoming SMTP traffic. The flaw manifests when remote attackers exploit the system's failure to properly handle malformed or invalid command sequences, particularly binary null characters and other invalid command streams that are sent directly to the SMTP proxy service.
The technical nature of this vulnerability aligns with CWE-20, which describes improper input validation, and demonstrates how insufficient sanitization of network input can lead to system instability. The SMTP Security Server proxy in Check Point FireWall-1 versions 4.0 and 4.1 lacks robust error handling for malformed SMTP command sequences, allowing attackers to send specially crafted streams of invalid commands that cause the proxy service to crash or become unresponsive. This occurs because the system does not implement proper buffer overflow protection or command validation routines that would normally filter out binary zeros and other non-standard command characters that are not part of legitimate SMTP protocol communication.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall security posture of networks relying on Check Point FireWall-1 for email protection. When the SMTP proxy service becomes unavailable due to this denial of service attack, legitimate email traffic is blocked while the system attempts to recover from the crash. This creates a window of vulnerability where email communications are disrupted, potentially affecting business operations and communication flows. The attack vector is particularly concerning as it requires minimal technical expertise to execute, making it accessible to attackers with basic network knowledge. The vulnerability also falls under ATT&CK technique T1498, which covers denial of service attacks, and specifically targets network security appliances that are critical infrastructure components.
Mitigation strategies for this vulnerability should include immediate implementation of firmware updates from Check Point to address the input validation deficiencies in the SMTP proxy service. Organizations should also deploy network monitoring solutions to detect unusual command sequences that may indicate exploitation attempts, and implement rate limiting or connection throttling mechanisms to prevent rapid flooding of invalid commands. The solution approach aligns with security best practices outlined in NIST SP 800-53 for access control and system monitoring, requiring organizations to maintain updated security configurations and implement proper input validation controls. Additionally, network administrators should consider implementing redundant email security services and establishing incident response procedures specifically designed to handle proxy service failures, as this vulnerability demonstrates how a single component failure can impact broader email infrastructure availability.