CVE-2001-1474
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSSH before 2.0 disables host key checking when connecting to the localhost, which allows remote attackers to silently redirect connections to the localhost by poisoning the client's DNS cache.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceSSH versions prior to 2.0 disable host key verification when connecting to localhost, creating a trust-on-first-use failure. Attackers can exploit this by performing DNS cache poisoning to redirect SSH connections intended for localhost to malicious hosts, enabling man-in-the-middle attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.2.24= 1.2.25= 1.2.26= 1.2.27= 1.2.28= 1.2.29= 1.2.30= 1.2.31CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:N/I:P/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Determine the installed SSH versionRun 'ssh -V' or 'ssh -v' to display the SSH client version. Also check the SSH server version if running sshd using 'sshd -v' or by checking the installed package.Affected if The version displayed is between 1.2.24 and 1.2.31 inclusive (e.g., 1.2.24, 1.2.27, 1.2.31)
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Verify the SSH service is runningCheck if the SSH daemon is active using 'ps aux | grep sshd' or 'systemctl status sshd' (or 'service sshd status' on older systems).Affected if The SSH service is running and the version from step 1 is in the affected range 1.2.24-1.2.31
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Inspect SSH client configuration for localhost host key settingsReview SSH client config files (/etc/ssh/ssh_config or ~/.ssh/config) for any directives that disable StrictHostKeyChecking or enable host key skipping specifically for localhost connections. Search for 'localhost' entries with RelaxHostKeyChecking or equivalent options.Affected if Configuration contains options that skip or relax host key verification for localhost connections
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Test host key verification behavior on localhost connectionAttempt an SSH connection to localhost (ssh localhost) and observe whether the client prompts to verify the host key, automatically adds it to known_hosts, or connects without any host key verification prompt.Affected if SSH connects to localhost without prompting to verify the host key, indicating host key verification is disabled for localhost
You are affected if the installed SSH version is between 1.2.24 and 1.2.31 AND the client bypasses host key verification when connecting to localhost.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade SSH to version 2.0 or later where host key checking is properly enforced for all connections, including localhost. If upgrade is not feasible, disable any configuration options that skip host key verification for localhost.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2001-1474 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2001-1474 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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