CVE-2002-1357 in PuTTY
Summary
by MITRE
Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code, as demonstrated by the SSHredder SSH protocol test suite.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability described in CVE-2002-1357 represents a critical flaw in SSH2 implementations that stems from inadequate validation of packet length specifications within the Secure Shell protocol. This issue affects both server and client implementations across multiple SSH2 deployments, creating a widespread security concern that impacts the fundamental integrity of secure remote access communications. The flaw specifically manifests when SSH2 systems encounter packets or data elements containing malformed length specifiers that do not conform to expected protocol standards, potentially leading to unpredictable system behavior and severe operational consequences.
The technical root cause of this vulnerability lies in the improper handling of length fields within SSH2 packet structures, which constitutes a classic buffer over-read or under-read condition that can trigger memory corruption. When SSH2 implementations process packets with incorrect length specifiers, the parsing logic fails to properly validate the boundary conditions of data elements, leading to potential memory access violations or stack corruption. This type of vulnerability maps directly to CWE-129, which describes improper validation of length specifiers, and CWE-121, which covers stack-based buffer overflow conditions. The flaw demonstrates characteristics of a memory safety issue where the protocol implementation does not adequately protect against malformed input that could be exploited to manipulate memory layout or execution flow.
The operational impact of CVE-2002-1357 extends beyond simple denial of service to potentially enable remote code execution, making it particularly dangerous in production environments where SSH2 is used for critical system administration and remote access. Attackers can leverage this vulnerability through the SSHredder SSH protocol test suite, which systematically tests various protocol implementations for weaknesses. The attack surface includes any SSH2 server or client that processes incoming packets without proper length validation, creating a significant risk for network infrastructure, enterprise systems, and any organization relying on SSH2 for secure communications. This vulnerability directly aligns with ATT&CK technique T1210, which covers exploitation of remote services, and T1499, which covers network disruption through service availability attacks.
Mitigation strategies for this vulnerability require immediate implementation of protocol validation patches across all affected SSH2 implementations, with particular emphasis on ensuring proper length field validation before any packet processing occurs. Organizations should deploy updated SSH2 server and client software versions that include proper input validation mechanisms, while also implementing network segmentation and access controls to limit exposure. The remediation process must include thorough testing of patched implementations to ensure that the validation logic does not introduce performance degradation or compatibility issues with legitimate protocol usage. Additionally, security monitoring should be enhanced to detect anomalous packet patterns that might indicate exploitation attempts, and network administrators should consider implementing intrusion detection systems specifically configured to identify SSH2 protocol anomalies that could indicate exploitation of this vulnerability.