CVE-2023-38408
Openbsd Openssh ≤ 9.3
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2023-38408 is a critical-severity Unquoted Search Path or Element (CWE-428) vulnerability in Openbsd Openssh. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked in the top 0.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
The vulnerability is an insufficiently trustworthy search path in the PKCS#11 feature of ssh-agent within OpenSSH versions prior to 9.3p2. This stems from an incomplete remediation of CVE-2016-10009 and allows code in directories such as /usr/lib to be loaded into the agent even when that code cannot be assumed safe. The issue is tracked as CWE-428 and carries a CVSS 3.1 score of 9.8.
An attacker who can arrange for a victim’s ssh-agent to be forwarded to a system under their control can supply a malicious PKCS#11 module that ssh-agent will load, resulting in remote code execution on the victim’s host with the privileges of the agent process. No authentication or user interaction is required once the agent forwarding occurs.
Upstream advisories and the OpenSSH 9.3p2 release notes direct users to upgrade immediately; the fix restricts the search path used for PKCS#11 providers when an agent is forwarded. Public exploit code has been posted, and the EPSS score has reached a peak of 0.6999 with a current value of 0.6435, indicating sustained exploitation interest after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-42225
Vulnerability Data
The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. (Code in /usr/lib is not necessarily safe for loading into ssh-agent.)…
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NOTE: this issue exists because of an incomplete fix for CVE-2016-10009.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent path-handling flaws such as unquoted elements during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect unquoted search-path issues before deployment.
Enforcing controlled software installation can prevent unquoted search-path elements in executables and scripts.
Secure development lifecycle practices include input validation and path handling that reduce unquoted search-path weaknesses.
Secure system architecture and engineering principles require safe path construction and quoting conventions.
Secure coding standards directly mandate quoting search paths and avoiding unsafe path construction.
Change-management processes can enforce review of path-handling changes that might introduce unquoted elements.