In ssh-agent in OpenSSH before 9.6, certain destination constraints can be incompletely applied. When destination constraints are specified during the addition of PKCS#11-hosted private keys, these constraints are only applied to the first key, even if a PKCS#11 token returns multiple keys. This flaw can lead to unauthorized access and management of keys.
The CVSS score of 5.5 classifies this vulnerability as medium severity. Despite not requiring high privileges or user interaction, the potential impact on confidentiality is high. Organizations utilizing OpenSSH versions prior to 9.6 should be aware of the risks posed by this vulnerability.
Risk to organizations includes the potential for unauthorized key usage, which can compromise sensitive operations. Organizations should prioritize patching immediately to mitigate this vulnerability.
Currently, there are no known exploits available for this vulnerability, and it is not listed in the Known Exploited Vulnerabilities (KEV) catalog. However, the low exploitability score indicates a medium level of risk, necessitating timely action.
Organizations should review their OpenSSH deployments and ensure that they are updated to version 9.6 or later to prevent potential exploitation.
Vulnerability Details
The vulnerability affects OpenSSH versions prior to 9.6 and is characterized by incomplete application of destination constraints during the addition of PKCS#11-hosted private keys. This issue is particularly concerning as it may allow unauthorized access to keys that should be restricted.
The CVSS 3.1 vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, indicating a local attack vector with low complexity and low privileges required. The high confidentiality impact further underscores the importance of addressing this vulnerability.
This vulnerability applies to Debian and OpenBSD systems, specifically affecting OpenSSH versions from 8.9 up to but not including 9.6.
Technical Analysis
The root cause of this vulnerability lies in the implementation of destination constraints within ssh-agent. When adding multiple keys from a PKCS#11 token, only the first key's constraints are enforced, leaving subsequent keys vulnerable to unauthorized access.
The attack vector is local, meaning an attacker requires access to the system where OpenSSH is running. The attack complexity is low, as the attacker does not need to engage in intricate techniques to exploit the vulnerability.
The privileges required are low, as the attacker may need only limited access to execute the necessary commands. User interaction is not required, making this vulnerability particularly dangerous.
The confidentiality impact is high, as it allows unauthorized access to sensitive keys, while integrity and availability impacts are negligible.
Risk & Impact Analysis
Organizations deploying OpenSSH prior to version 9.6 are at risk of unauthorized key access due to this vulnerability. Given that many systems rely on SSH for secure communication and remote access, the potential for exploitation exists, especially in environments where multiple keys are managed.
The urgency for remediation is medium. Organizations should address this vulnerability in their patch cycle to ensure that their systems remain secure. Given the high confidentiality impact, the risk of unauthorized access could lead to significant operational and reputational damage.
In terms of blast radius, organizations with extensive SSH deployments or those handling sensitive data should prioritize this vulnerability to avoid potential data breaches.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects all versions of OpenSSH from 8.9 up to, but not including, 9.6. Additionally, it impacts Debian Linux versions 11.0 and 12.0.
Mitigation & Remediation
To remediate this vulnerability, organizations should upgrade OpenSSH to version 9.6 or later. If a patch is unavailable, consider implementing configuration changes that limit access to sensitive keys.
Organizations may also benefit from conducting an application security assessment to identify potential weaknesses in their configurations.
Detection Guidance
Monitoring logs for unusual access patterns and key management anomalies can help in detecting potential exploitation attempts. Additionally, organizations should audit their SSH configurations regularly.
AppSecure Threat Intelligence Insight
The introduction of this vulnerability highlights the critical importance of ensuring that key management processes are robust and secure. Organizations should consider implementing comprehensive security testing practices, such as penetration testing, to assess the effectiveness of their existing security measures.
Additionally, organizations should remain updated on security advisories and patches from vendors, as timely updates can significantly reduce the risk profile associated with vulnerabilities such as this one.
As a strategic takeaway, fostering a culture of security awareness among employees can further enhance an organization’s resilience against exploited vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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