CVE-2019-19755
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 · uneditedethOS through 1.3.3 ships with SSH host keys baked into the installation image, which allows man-in-the-middle attacks and makes identification of all public IPv4 nodes trivial with Shodan.io. NOTE: as of 2019-12-01, the vendor indicated that they plan to fix this.
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 confidenceethOS through 1.3.3 ships with pre-generated SSH host keys embedded in the installation image. Since these host keys are identical across all installations, anyone with the image can perform man-in-the-middle attacks using the corresponding private keys, and can trivially discover all ethOS nodes on the internet by searching for the known SSH host key fingerprints in services like Shodan.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Identify ethOS versionCheck the ethOS version file (commonly in /etc/ethos or /opt/ethos) or run 'cat /etc/ethos-version' or similar version command provided by ethOSAffected if Version is 1.3.3 or lower (the vulnerable range is through 1.3.3)
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Locate SSH host keysCheck for SSH host key files in /etc/ssh/ (typically ssh_host_rsa_key, ssh_host_ecdsa_key, ssh_host_ed25519_key)Affected if SSH host key files exist in the default location
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Check host key fingerprintsRun 'ssh-keygen -lf /etc/ssh/ssh_host_rsa_key' and similar for other key types to obtain fingerprintsAffected if The fingerprints match known default values embedded in the ethOS image (identical across all installations)
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Verify key timestampsCheck file timestamps with 'ls -la /etc/ssh/ssh_host_*_key' - keys embedded in an image will show the original image build date rather than system installation dateAffected if Host keys have old timestamps predating the system's installation or first boot date
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Compare with other ethOS installationsIf you have access to multiple ethOS systems, compare SSH host key fingerprints across themAffected if Different ethOS systems have identical SSH host key fingerprints
A system is affected if it is running ethOS version 1.3.3 or lower AND has SSH host keys that are identical to the default keys embedded in the installation image.
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 dataRegenerate unique SSH host keys during first boot or initial configuration rather than embedding them in the image. Deployments should regenerate or rotate their SSH host keys immediately if using affected versions.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.
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Free · runs locallyCheck whether your project pulls in CVE-2019-19755 — 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-2019-19755 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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