Security Resilience

CVE-2023-38408

Openbsd Openssh ≤ 9.3

Public PoCHigh EPSS
Published
20 July 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.80 99.6th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

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 LSASS Memory (T1003.001); 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

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.)…

more

NOTE: this issue exists because of an incomplete fix for CVE-2016-10009.

CWE(s)
CWE-428

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1011 Exfiltration Over Other Network Medium Exfiltration
Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel.
attack.mitre.org →
T1016.001 Internet Connection Discovery Discovery
Adversaries may check for Internet connectivity on compromised systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-51767Same product: Fedoraproject Fedora
CVE-2024-5402Shared CWE-428
CVE-2019-25272Shared CWE-428
CVE-2020-37254Shared CWE-428
CVE-2016-20059Shared CWE-428
CVE-2023-3842Shared CWE-428
CVE-2020-37223Shared CWE-428
CVE-2020-37055Shared CWE-428
CVE-2025-41359Shared CWE-428
CVE-2016-20089Shared CWE-428

Affected Assets

openbsd
openssh
9.3 · ≤ 9.3
fedoraproject
fedora
37, 38

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.

PR.PS-06 partial match
blocks

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.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.5.4 Management responsibilities partial match
removes

References