CVE-2001-1473
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 · uneditedThe SSH-1 protocol allows remote servers to conduct man-in-the-middle attacks and replay a client challenge response to a target server by creating a Session ID that matches the Session ID of the target, but which uses a public key pair that is weaker than the target's public key, which allows the attacker to compute the corresponding private key and use the target's Session ID with the compromised key pair to masquerade as the target.
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-1 protocol contains a flaw where a malicious server can conduct a man-in-the-middle attack by replaying a client's challenge-response with a Session ID matching the target server, but using a cryptographically weaker public key pair. The attacker can compute the corresponding private key and use the target's Session ID with the compromised key to masquerade as the legitimate server.
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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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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Identify installed SSH versionRun 'ssh -V' or 'ssh -version' to obtain the SSH client version, or check the SSH server version using 'sshd -V' or reviewing the installed package (e.g., 'dpkg -l | grep ssh' or 'rpm -qa | grep ssh')Affected if The version matches 1.2.24, 1.2.25, 1.2.26, 1.2.27, 1.2.28, 1.2.29, 1.2.30, or 1.2.31
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Check SSH server protocol configurationReview the SSH server configuration file (commonly /etc/ssh/sshd_config) for the 'Protocol' directive. If absent, check the default behavior by running 'sshd -T' and searching for the protocol settingAffected if The Protocol directive is set to '1' or '1,2', meaning SSH-1 is enabled
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Check SSH client protocol configurationReview the SSH client configuration file (commonly ~/.ssh/config or /etc/ssh/ssh_config) for the 'Protocol' directive, or test with 'ssh -v' connection attempt and observe which protocol is negotiatedAffected if The client allows or prefers SSH-1 protocol connections (Protocol 1 or 1,2)
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Verify active SSH connections using protocol 1Use 'netstat -tnp' or 'ss -tnp' while SSH connections are active, then attempt an SSH connection with verbose output 'ssh -v user@host' to observe which protocol version is being usedAffected if SSH-1 protocol is actually being negotiated or used in active sessions
You are affected if you run an SSH version between 1.2.24 and 1.2.31 inclusive AND have SSH-1 protocol enabled in your client or server configuration, allowing protocol-level man-in-the-middle attacks.
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 dataDisable SSH-1 protocol support on SSH servers and clients, forcing all connections to use SSH-2 which contains corrected protocol specifications. Verify that all legitimate clients and servers support SSH-2 before disabling SSH-1.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2001-1473 — 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-2001-1473 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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- Version or environment caveats, and links to real fixes
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