CVE-2001-0144 in OpenSSH
Summary
by MITRE
CORE SDI SSH1 CRC-32 compensation attack detector allows remote attackers to execute arbitrary commands on an SSH server or client via an integer overflow.
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Analysis
by VulDB Data Team • 10/08/2025
The vulnerability identified as CVE-2001-0144 represents a critical security flaw in SSH implementations that specifically targets the CRC-32 compensation attack detector within CORE SDI SSH1 software. This vulnerability operates at the protocol level of Secure Shell communications and exploits a fundamental mathematical error in how integer values are processed during cryptographic operations. The flaw exists within the implementation of the SSH1 protocol's integrity checking mechanism, where the system fails to properly validate input parameters during the compensation attack detection process.
The technical exploitation of this vulnerability occurs through an integer overflow condition that arises when the SSH server or client processes specially crafted data packets containing malformed CRC-32 values. When the system attempts to calculate compensation values for detected attacks, the integer arithmetic overflow causes the system to behave unpredictably, potentially allowing an attacker to manipulate the execution flow of the affected software. This type of vulnerability falls under CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how mathematical boundary conditions can be exploited to gain unauthorized system access.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise capabilities for remote attackers. An attacker who successfully exploits this vulnerability can execute arbitrary commands on the affected SSH server or client, effectively gaining complete control over the targeted system. This allows for data exfiltration, system modification, privilege escalation, and the establishment of persistent access points. The vulnerability affects both server and client implementations, meaning that either component in an SSH communication chain could be compromised. Attackers can leverage this flaw without requiring authentication to the SSH service itself, making it particularly dangerous as it can be exploited against systems that are otherwise properly secured.
The exploitation of this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to remote code execution and privilege escalation. The attack vector specifically corresponds to ATT&CK technique T1210, which covers exploitation of remote services, and T1068, which addresses local privilege escalation. Organizations implementing SSH services must understand that this vulnerability represents a fundamental flaw in protocol implementation that cannot be mitigated through traditional network security measures. The integer overflow condition creates a deterministic path for arbitrary code execution, making it a preferred target for attackers seeking persistent access to network infrastructure. Remediation requires immediate patching of affected systems and implementation of proper input validation measures that prevent integer overflow conditions in cryptographic protocol implementations. Organizations should also consider implementing network segmentation and monitoring to detect potential exploitation attempts, as the attack can occur without authentication and may not immediately trigger obvious security alerts.
This vulnerability demonstrates the critical importance of proper integer handling in security-critical applications and highlights how seemingly minor implementation flaws can result in catastrophic security breaches. The fact that this vulnerability was present in widely deployed SSH implementations underscores the need for comprehensive security testing of cryptographic protocols and the importance of maintaining up-to-date security patches across all network infrastructure components.