CVE-2025-61984 is a low-severity vulnerability identified in OpenSSH versions prior to 10.1. This vulnerability allows control characters in usernames that originate from certain possibly untrusted sources, which may lead to code execution when a ProxyCommand is utilized. The untrusted sources include command line inputs and %-sequence expansion from configuration files, while a configuration file that provides a complete literal username is not categorized as an untrusted source.
The severity of this vulnerability is rated low, with a CVSS score of 3.6. It is essential for organizations to understand the implications of this vulnerability, as it can potentially be exploited through local attack vectors. Organizations that use OpenSSH should prioritize addressing this vulnerability to mitigate risks associated with code execution.
Currently, there are no known exploits for this vulnerability, and it is marked as 'Awaiting Analysis.' Nevertheless, organizations should remain vigilant and prepare to implement necessary patches as they become available. It is recommended that users of OpenSSH update their software promptly to the latest version to enhance security.
The urgency for defenders is moderate. Organizations should schedule remediation during their patch cycles to address this vulnerability and improve their overall security posture.
Vulnerability Details
This vulnerability allows control characters in usernames that originate from certain possibly untrusted sources, potentially leading to code execution when a ProxyCommand is used. The untrusted sources are the command line and %-sequence expansion of a configuration file. A configuration file that provides a complete literal username is not categorized as an untrusted source.
The CVSS score for CVE-2025-61984 is 3.6, indicating a low severity level. The attack vector is classified as local, and it requires low privileges with no user interaction. The impacts on confidentiality and integrity are both rated as low, while availability is unaffected.
Technical Analysis
The root cause of this vulnerability stems from the ability of control characters to be included in usernames, combined with the utilization of ProxyCommand in SSH configurations. This can create an opening for code execution if exploited properly. The attack complexity is considered high, as it requires specific conditions to be met, including the presence of malicious input from untrusted sources.
Given that the attack vector is local, it implies that an attacker would need access to the local network or system to exploit this vulnerability. The low privileges required suggest that even users with limited access could potentially exploit the issue, making it a noteworthy risk.
Risk & Impact Analysis
Risk to organizations includes potential unauthorized code execution, which could lead to data breaches or other malicious activities. The blast radius is limited to systems where the vulnerable version of OpenSSH is deployed, but if exploited, it may allow attackers to escalate privileges or execute arbitrary commands.
Organizations should assess the presence of OpenSSH in their infrastructure and prioritize patching this vulnerability. While the CVSS score is low, the implications of any potential exploitation should not be underestimated. Monitoring for unusual SSH activity is recommended to detect potential attempts to exploit this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of OpenSSH prior to 10.1 are affected by this vulnerability. Organizations should upgrade to the latest version to mitigate the risk.
Mitigation & Remediation
Organizations should prioritize patching OpenSSH immediately to address this vulnerability. The recommended action is to upgrade to version 10.1 or later. If immediate patching is not feasible, consider implementing configuration changes to restrict the usage of ProxyCommand or control character inputs in usernames. Additionally, monitoring SSH logs for unusual activity is advisable.
Detection Guidance
Organizations should monitor logs for any anomalies related to SSH connections, particularly those that involve ProxyCommand usage. Look for unexpected usernames or control characters in usernames that may indicate attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2025-61984 lies in its potential to highlight the risks associated with input validation in usernames and configurations. This vulnerability serves as a reminder for security teams to implement robust input validation mechanisms, especially in services that process user input.
Organizations should consider reviewing their security policies and configurations to ensure that they prevent similar vulnerabilities in the future. Educating development teams on secure coding practices and the importance of proper input handling is crucial in mitigating such vulnerabilities.
Continuous security testing can help to identify similar weaknesses before they are exploited.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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