CVE-2003-0047 in SecureCRT
Summary
by MITRE
SSH2 clients for VanDyke (1) SecureCRT 4.0.2 and 3.4.7, (2) SecureFX 2.1.2 and 2.0.4, and (3) Entunnel 1.0.2 and earlier, do not clear logon credentials from memory, including plaintext passwords, which could allow attackers with access to memory to steal the SSH credentials.
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Analysis
by VulDB Data Team • 07/14/2019
This vulnerability affects SecureCRT SecureFX and Entunnel SSH clients developed by VanDyke Software, specifically versions 4.0.2 and 3.4.7 for SecureCRT, 2.1.2 and 2.0.4 for SecureFX, and Entunnel 1.0.2 and earlier. The flaw represents a critical memory handling issue where authentication credentials including plaintext passwords remain accessible in memory even after successful authentication or session termination. This design flaw creates an exploitable condition where malicious actors with access to the target system's memory can extract stored credentials through memory dumping techniques or direct memory inspection. The vulnerability directly violates security best practices for credential management and represents a classic example of insecure credential storage in memory, which is categorized under CWE-256.
The technical implementation of this vulnerability stems from the client applications failing to properly sanitize memory regions containing authentication data after use. When users establish SSH connections, their credentials are temporarily stored in memory for authentication purposes, but the applications do not explicitly clear these memory segments or overwrite them with random data before releasing them back to the operating system. This memory persistence allows attackers who gain access to the process memory through techniques such as process dumping, memory inspection, or exploitation of other vulnerabilities to extract plaintext passwords and other authentication tokens. The vulnerability is particularly concerning in environments where multiple users share systems or where privilege escalation attacks may occur, as it provides attackers with a direct path to obtain valid authentication credentials without needing to bypass network-level protections.
The operational impact of this vulnerability extends beyond simple credential theft, as it can enable attackers to establish persistent access to target systems through legitimate SSH connections. Once credentials are extracted from memory, attackers can use them to access not only the systems where the vulnerable clients are running but potentially other systems that rely on the same authentication credentials. This creates a cascading effect where a single compromised client installation can lead to broader network infiltration. The vulnerability also impacts the principle of least privilege and defense in depth, as it provides an additional attack vector that bypasses traditional network-based security controls. From an attacker's perspective, this represents a low-effort, high-reward technique that can be automated and combined with other exploitation methods to achieve persistent access and lateral movement within networks.
Mitigation strategies for this vulnerability should focus on immediate application updates from VanDyke Software, which would address the memory handling issues in the affected versions. Organizations should also implement memory protection mechanisms such as address space layout randomization and data execution prevention to make memory extraction attacks more difficult. System administrators should monitor for unauthorized process memory access and implement strict access controls on systems running vulnerable applications. Additionally, security teams should consider implementing credential rotation procedures and multi-factor authentication to reduce the impact of credential theft. The vulnerability highlights the importance of proper memory management in security-critical applications and aligns with ATT&CK technique T1003.001 for Credential Dumping, demonstrating how insecure memory handling can create persistent attack vectors that persist even after initial compromise attempts.