CVE-2002-1059 in SecureCRT
Summary
by MITRE
Buffer overflow in Van Dyke SecureCRT SSH client before 3.4.6, and 4.x before 4.0 beta 3, allows an SSH server to execute arbitrary code via a long SSH1 protocol version string.
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Analysis
by VulDB Data Team • 05/03/2025
The vulnerability described in CVE-2002-1059 represents a critical buffer overflow flaw within the Van Dyke SecureCRT SSH client software that affected versions prior to 3.4.6 and 4.0 beta 3. This issue specifically targets the SSH1 protocol version string handling mechanism, creating a potential pathway for remote code execution. The vulnerability arises from insufficient input validation and boundary checking when processing SSH protocol version strings from remote servers, allowing malicious actors to exploit this weakness through carefully crafted malicious SSH servers.
The technical implementation of this buffer overflow occurs during the initial SSH handshake process when the client receives the server's protocol version string. When an SSH server sends a version string that exceeds the allocated buffer space, the software fails to properly validate the input length before copying it into memory. This classic buffer overflow condition creates a situation where adjacent memory locations can be overwritten, potentially allowing an attacker to inject and execute arbitrary code with the privileges of the running SecureCRT process. The vulnerability specifically affects the SSH1 protocol implementation within the client software, making it particularly concerning for environments that still rely on legacy SSH protocols.
The operational impact of this vulnerability extends beyond simple remote code execution capabilities, as it can enable complete system compromise when exploited successfully. An attacker controlling a malicious SSH server could leverage this vulnerability to gain unauthorized access to systems running vulnerable SecureCRT clients, potentially leading to data exfiltration, privilege escalation, or establishment of persistent backdoors. The attack vector requires the victim to connect to a malicious SSH server, making social engineering or network compromise tactics potentially necessary for exploitation. This vulnerability particularly affects enterprise environments that use SecureCRT for remote system administration, as it could provide attackers with a direct pathway to compromise administrative access to critical infrastructure.
Mitigation strategies for CVE-2002-1059 should prioritize immediate patching of affected SecureCRT versions to the recommended secure releases. Organizations should implement network segmentation to limit exposure of vulnerable systems and consider disabling SSH1 protocol support where possible, as SSH2 protocol provides better security characteristics. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation that can be addressed through proper bounds checking and memory management practices. From an ATT&CK framework perspective, this vulnerability maps to T1021.004 for remote services and T1059 for command and scripting interpreter, representing a critical threat that requires immediate attention to prevent exploitation. Additionally, network monitoring should be enhanced to detect unusual SSH protocol version strings that might indicate exploitation attempts, and regular security assessments should verify that all SSH client implementations are updated to secure versions.