OpenBSD OpenSSH: Remote Code Execution (CVE-2023-38408)
Published Last modified Sources: BSI, Ubuntu, CVE.org, Siemens ProductCERT
What is affected, what to do
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.) NOTE: this issue exists because of an incomplete fix for CVE-2016-10009.
An exploit is publicly available. The available sources name no fixed version. Check the vendor guidance in the references below.
Conflicting version data — version display is hidden until the data is resolved.
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
9.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
9.8
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: BSI, Ubuntu, CVE.org, Siemens ProductCERT
79.7 %
EPSS score
High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
Source: FIRST EPSS, percentile 99.60
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 131.44 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- PoC (publicly reported)
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 9.8 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 9.8
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 79.7 %
- High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 99.60
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 15 October 2024
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-428
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
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.) NOTE: this issue exists because of an incomplete fix for CVE-2016-10009.
Source: BSI CSAF, BSI WID Portal, Ubuntu Security Notices, NVD (NIST), cvelistv5, siemens_advisory
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| openbsd | openssh |
|
|
| Oracle | Communications |
|
|
Vendors and products
Affected operating systems
| Linux | ubuntu | openssh | focal |
| Linux | ubuntu | openssh | jammy |
| Linux | ubuntu | openssh | lunar |
| Other | fedoraproject | fedora | 37 |
| Other | fedoraproject | fedora | 38 |
Weakness classes (CWE)
CWE-428Unquoted Search Path or Element
Base
The product uses a search path that contains an unquoted element, in which the element contains whitespace or other separators. This can cause the product to access resources in a parent path.
Entry at MITRE CWE-428
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| Packet Storm | OpenSSH Forwarded SSH Agent Remote Code Execution (opens in a new tab)packetstormsecurity.com | PoC (publicly reported)reported, not verified | — |
| PoC-in-GitHub (nomi-sec) | CVE-2023-38408 (opens in a new tab)github.com | PoC (publicly reported)reported, not verified |
References & sources
- news.ycombinator.comitem?id=36790196
- blog.qualys.comvulnerabilities-threat-research/2023/07/19/cve-2023-38408-remot…
- qualys.com2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt
- github.comopenbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca
- github.comopenbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8
- github.comopenbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d
- openssh.comtxt/release-9.3p2
- openssh.comsecurity.html
- security.gentoo.orgGLSA-202307-01Vendor advisory
- openwall.com[oss-security] 20230719 Re: CVE-2023-38408: Remote Code Execution in OpenSSH's forwarded ssh-agentMailing list
- openwall.com[oss-security] 20230720 Re: Announce: OpenSSH 9.3p2 releasedMailing list
- packetstormsecurity.comfiles/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.…
- lists.fedoraproject.orgFEDORA-2023-878e04f4aeVendor advisory
- lists.fedoraproject.orgFEDORA-2023-79a18e1725Vendor advisory
- security.netapp.comadvisory/ntap-20230803-0010
- lists.debian.org[debian-lts-announce] 20230817 [SECURITY] [DLA 3532-1] openssh security updateMailing list
- openwall.com[oss-security] 20230922 Re: illumos (or at least danmcd) membership in the distros listMailing list
- openwall.com[oss-security] 20230922 Re: illumos (or at least danmcd) membership in the distros listMailing list
- support.apple.comkb/HT213940
- vicarius.iovsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023…
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedSiemens ADP
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2023/38xxx/CVE-2023-38408.json">CVE-2023-38408</a>Reference added —https://cert-portal.siemens.com/productcert/html/ssa-398330.htmlSource identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
Record modifiedMITRE
New references:- http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html
- http://www.openwall.com/lists/oss-security/2023/07/20/1
- http://www.openwall.com/lists/oss-security/2023/07/20/2
- http://www.openwall.com/lists/oss-security/2023/09/22/11
and 8 more references
Show 52 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.htmlReference added —http://www.openwall.com/lists/oss-security/2023/07/20/1Reference added —http://www.openwall.com/lists/oss-security/2023/07/20/2Reference added —http://www.openwall.com/lists/oss-security/2023/09/22/11Reference added —http://www.openwall.com/lists/oss-security/2023/09/22/9Reference added —https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agentReference added —https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8Reference added —https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351dReference added —https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7caReference added —https://lists.debian.org/debian-lts-announce/2023/08/msg00021.htmlReference added —https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBTJJINE2I3FHAUKKNQWMFGYMLSMWKQ/Reference added —https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXVQS6ZYTULFAK3TEJHRLKZALJS3AOU/Reference added —https://news.ycombinator.com/item?id=36790196Reference added —https://security.gentoo.org/glsa/202307-01Reference added —https://security.netapp.com/advisory/ntap-20230803-0010/Reference added —https://support.apple.com/kb/HT213940Reference added —https://www.openssh.com/security.htmlReference added —https://www.openssh.com/txt/release-9.3p2Reference added —https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txtReference added —https://www.vicarius.io/vsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023-38408Reference removed http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html—Reference removed http://www.openwall.com/lists/oss-security/2023/07/20/1—Reference removed http://www.openwall.com/lists/oss-security/2023/07/20/2—Reference removed http://www.openwall.com/lists/oss-security/2023/09/22/11—Reference removed http://www.openwall.com/lists/oss-security/2023/09/22/9—Reference removed https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agent—Reference removed https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8—Reference removed https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d—Reference removed https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca—Reference removed https://lists.debian.org/debian-lts-announce/2023/08/msg00021.html—Reference removed https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBTJJINE2I3FHAUKKNQWMFGYMLSMWKQ/—Reference removed https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXVQS6ZYTULFAK3TEJHRLKZALJS3AOU/—Reference removed https://news.ycombinator.com/item?id=36790196—Reference removed https://security.gentoo.org/glsa/202307-01—Reference removed https://security.netapp.com/advisory/ntap-20230803-0010/—Reference removed https://support.apple.com/kb/HT213940—Reference removed https://www.openssh.com/security.html—Reference removed https://www.openssh.com/txt/release-9.3p2—Reference removed https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt—Reference removed https://www.vicarius.io/vsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023-38408—Reference type removed http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html Types: Exploit, Third Party Advisory, VDB Entry—Reference type removed http://www.openwall.com/lists/oss-security/2023/07/20/1 Types: Exploit, Mailing List, Third Party Advisory—Reference type removed http://www.openwall.com/lists/oss-security/2023/07/20/2 Types: Mailing List, Third Party Advisory—Reference type removed https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agent Types: Third Party Advisory—Reference type removed https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8 Types: Patch—Reference type removed https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d Types: Patch—Reference type removed https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca Types: Patch—Reference type removed https://news.ycombinator.com/item?id=36790196 Types: Issue Tracking, Patch—Reference type removed https://security.gentoo.org/glsa/202307-01 Types: Third Party Advisory—Reference type removed https://www.openssh.com/security.html Types: Vendor Advisory—Reference type removed https://www.openssh.com/txt/release-9.3p2 Types: Release Notes—Reference type removed https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt Types: Exploit, Third Party Advisory—Source identifier: cve@mitre.org
Record modifiedCVE Program
New references:- http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html
- http://www.openwall.com/lists/oss-security/2023/07/20/1
- http://www.openwall.com/lists/oss-security/2023/07/20/2
- http://www.openwall.com/lists/oss-security/2023/09/22/11
and 8 more references
Show 52 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.htmlReference added —http://www.openwall.com/lists/oss-security/2023/07/20/1Reference added —http://www.openwall.com/lists/oss-security/2023/07/20/2Reference added —http://www.openwall.com/lists/oss-security/2023/09/22/11Reference added —http://www.openwall.com/lists/oss-security/2023/09/22/9Reference added —https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agentReference added —https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8Reference added —https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351dReference added —https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7caReference added —https://lists.debian.org/debian-lts-announce/2023/08/msg00021.htmlReference added —https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBTJJINE2I3FHAUKKNQWMFGYMLSMWKQ/Reference added —https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXVQS6ZYTULFAK3TEJHRLKZALJS3AOU/Reference added —https://news.ycombinator.com/item?id=36790196Reference added —https://security.gentoo.org/glsa/202307-01Reference added —https://security.netapp.com/advisory/ntap-20230803-0010/Reference added —https://support.apple.com/kb/HT213940Reference added —https://www.openssh.com/security.htmlReference added —https://www.openssh.com/txt/release-9.3p2Reference added —https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txtReference added —https://www.vicarius.io/vsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023-38408Reference removed http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html—Reference removed http://www.openwall.com/lists/oss-security/2023/07/20/1—Reference removed http://www.openwall.com/lists/oss-security/2023/07/20/2—Reference removed http://www.openwall.com/lists/oss-security/2023/09/22/11—Reference removed http://www.openwall.com/lists/oss-security/2023/09/22/9—Reference removed https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agent—Reference removed https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8—Reference removed https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d—Reference removed https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca—Reference removed https://lists.debian.org/debian-lts-announce/2023/08/msg00021.html—Reference removed https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBTJJINE2I3FHAUKKNQWMFGYMLSMWKQ/—Reference removed https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXVQS6ZYTULFAK3TEJHRLKZALJS3AOU/—Reference removed https://news.ycombinator.com/item?id=36790196—Reference removed https://security.gentoo.org/glsa/202307-01—Reference removed https://security.netapp.com/advisory/ntap-20230803-0010/—Reference removed https://support.apple.com/kb/HT213940—Reference removed https://www.openssh.com/security.html—Reference removed https://www.openssh.com/txt/release-9.3p2—Reference removed https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt—Reference removed https://www.vicarius.io/vsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023-38408—Reference type removed http://packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html Types: Exploit, Third Party Advisory, VDB Entry—Reference type removed http://www.openwall.com/lists/oss-security/2023/07/20/1 Types: Exploit, Mailing List, Third Party Advisory—Reference type removed http://www.openwall.com/lists/oss-security/2023/07/20/2 Types: Mailing List, Third Party Advisory—Reference type removed https://blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code-execution-in-opensshs-forwarded-ssh-agent Types: Third Party Advisory—Reference type removed https://github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8 Types: Patch—Reference type removed https://github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d Types: Patch—Reference type removed https://github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca Types: Patch—Reference type removed https://news.ycombinator.com/item?id=36790196 Types: Issue Tracking, Patch—Reference type removed https://security.gentoo.org/glsa/202307-01 Types: Third Party Advisory—Reference type removed https://www.openssh.com/security.html Types: Vendor Advisory—Reference type removed https://www.openssh.com/txt/release-9.3p2 Types: Release Notes—Reference type removed https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt Types: Exploit, Third Party Advisory—Source identifier: af854a3a-2127-422b-91ae-364da2661108
Embed badge
Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.
<a href="https://intel.neosec.eu/en/cve/CVE-2023-38408"><img src="https://intel.neosec.eu/badge/cve/CVE-2023-38408.svg?lang=en" alt="CVE-2023-38408 – NEOSEC Intel" height="20"></a>