CVE-2008-0132 in FortressSSH
Summary
by MITRE
Pragma FortressSSH 5.0 Build 4 Revision 293 and earlier handles long input to sshd.exe by creating an error-message window and waiting for the administrator to click in this window before terminating the sshd.exe process, which allows remote attackers to cause a denial of service (connection slot exhaustion) via a flood of SSH connections with long data objects, as demonstrated by (1) a long list of keys and (2) a long username.
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Analysis
by VulDB Data Team • 01/13/2025
The vulnerability identified as CVE-2008-0132 affects Pragma FortressSSH version 5.0 Build 4 Revision 293 and earlier implementations, representing a significant denial of service weakness in SSH server software. This flaw manifests when the sshd.exe process encounters excessively long input data, triggering an erroneous behavior that fundamentally undermines system availability. The vulnerability operates through a specific mechanism where the software generates an error-message window requiring administrator interaction before proceeding with process termination. This design decision creates a critical operational bottleneck that remote attackers can exploit systematically.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the sshd.exe component. When malicious actors submit SSH connections containing long data objects such as extended key lists or overly lengthy usernames, the system's response mechanism becomes inherently flawed. The software's architecture fails to properly manage resource allocation during error conditions, leading to connection slot exhaustion rather than graceful handling of malformed input. This behavior directly violates secure coding principles and demonstrates poor resource management practices that are commonly addressed in cybersecurity frameworks such as the CWE (Common Weakness Enumeration) catalog under weakness categories related to resource management and input validation.
The operational impact of this vulnerability extends beyond simple service disruption to create substantial system instability and availability concerns. Attackers can systematically flood SSH servers with connections containing long data objects, causing the server to consume available connection slots indefinitely while waiting for administrator intervention. This creates a cascading effect where legitimate users cannot establish new connections, effectively rendering the SSH service unavailable to authorized personnel. The vulnerability particularly affects environments where SSH access is critical for system administration, as it can be exploited to deny legitimate administrative access to systems. Network security professionals should recognize this as a classic example of a resource exhaustion attack pattern that aligns with ATT&CK technique T1499.004 for Network Denial of Service, where attackers leverage system design flaws to consume available resources.
Mitigation strategies for this vulnerability must address both immediate operational concerns and long-term architectural improvements. System administrators should immediately upgrade to Pragma FortressSSH versions that address this specific flaw, as the vulnerability is resolved in later releases through improved input handling and error management. Organizations should implement connection rate limiting and input length restrictions at network boundaries to prevent exploitation attempts from reaching vulnerable systems. Additionally, security monitoring should include detection of unusual error message window generation patterns and connection slot exhaustion behaviors. The vulnerability highlights the importance of proper error handling design in security-critical applications and serves as a reminder of the necessity for implementing robust resource management practices that prevent denial of service conditions through inadequate input validation.