CVE-2017-5242
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 · uneditedNexpose and InsightVM virtual appliances downloaded between April 5th, 2017 and May 3rd, 2017 contain identical SSH host keys. Normally, a unique SSH host key should be generated the first time a virtual appliance boots.
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 confidenceNexpose and InsightVM virtual appliances downloaded during a one-month window contain hardcoded SSH host keys rather than generating unique keys on first boot. This means multiple customer appliances share identical SSH host keys, allowing an attacker who obtains the private key to perform man-in-the-middle attacks against any affected appliance or impersonate those servers to connected clients.
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>= 2017-04-05, <= 2017-05-03CVSS 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
- High
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/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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Confirm InsightVM applianceIdentify if the system is a Rapid7 InsightVM or InsightVM virtual appliance by checking system branding, hostname, or product documentationAffected if System is not an InsightVM virtual appliance - this CVE only applies to that specific product
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Check appliance deployment dateDetermine when the virtual appliance was downloaded, deployed, or first powered on. Check VM creation timestamp, system installation date, or deployment recordsAffected if Appliance was downloaded or deployed between 2017-04-05 and 2017-05-03 inclusive
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Inspect SSH host keysExamine SSH host keys in /etc/ssh/ directory (ssh_host_rsa_key, ssh_host_ecdsa_key, ssh_host_ed25519_key). Compare against known compromised keys or check if identical keys appear across multiple appliancesAffected if SSH host keys match known hardcoded values from the affected deployment window or are shared with other customer appliances
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Verify SSH service statusCheck if the SSH service is enabled and running on the appliance using systemctl status sshd or service ssh statusAffected if SSH service is active - the vulnerability only manifests when SSH is enabled and accepting connections
User is affected if the system is an InsightVM virtual appliance deployed during the vulnerable window (2017-04-05 to 2017-05-03) with SSH enabled and hardcoded SSH host keys present in /etc/ssh/.
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.
dbcve · scopedRegenerate unique SSH host keys on all affected appliances by removing existing keys from /etc/ssh/ and restarting the SSH service, then update client known_hosts entries to prevent authentication failures.
Redeploy with a virtual appliance image downloaded after May 3rd, 2017
- Regenerate the SSH host keys on the affected virtual appliance by running: ssh-keygen -A
- Alternatively, redeploy the virtual appliance using an image downloaded after May 3rd, 2017 which will generate unique SSH host keys on first boot
- After regenerating keys, update known_hosts files on any clients that previously connected to avoid man-in-the-middle attack warnings
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 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-2017-5242 — 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-2017-5242 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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