CVE-2020-15387
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 host SSH servers of Brocade Fabric OS before Brocade Fabric OS v7.4.2h, v8.2.1c, v8.2.2, v9.0.0, and Brocade SANnav before v2.1.1 utilize keys of less than 2048 bits, which may be vulnerable to man-in-the-middle attacks and/or insecure SSH communications.
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 confidenceBrocade Fabric OS and SANnav SSH servers use RSA host keys smaller than 2048 bits, which are cryptographically weak and vulnerable to factorization attacks, allowing potential man-in-the-middle attackers to intercept or impersonate SSH communications.
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< 2.1.1< 7.4.2>= 8.2.0, < 8.2.1= 7.4.2= 7.4.2a= 7.4.2b= 7.4.2c= 7.4.2d= 7.4.2f= 7.4.2g= 8.2.1= 8.2.1a= 8.2.1bCVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:H/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 the installed product and versionAccess the device management interface or CLI and retrieve the Fabric OS or SANnav version information. For Fabric OS, use 'version' or 'firmwareShow' command. For SANnav, check the About or Diagnostics page in the web UI.Affected if The version matches any of the following: SANnav < 2.1.1; Fabric OS < 7.4.2; Fabric OS 7.4.2, 7.4.2a, 7.4.2b, 7.4.2c, 7.4.2d, 7.4.2f, 7.4.2g; Fabric OS >= 8.2.0 and < 8.2.1; Fabric OS 8.2.1, 8.2.1a, 8.2.1b
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Confirm SSH server is enabledCheck if the SSH service is configured and active on the device. In Fabric OS CLI, use 'sshUtil show' or check running services. In SANnav, verify SSH access is permitted in the administration settings.Affected if SSH server is enabled and accessible on the affected product version, as the vulnerability exists in the SSH host key generation.
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Retrieve and inspect SSH host key sizeIf SSH access is available, connect to the device and examine the SSH host keys in the /etc/ssh/ directory (or equivalent) using commands like 'ssh-keygen -lf /etc/ssh/ssh_host_rsa_key.pub' to check the RSA key length.Affected if The RSA host key is smaller than 2048 bits, indicating the cryptographically weak keys described in the CVE.
You are affected if your device runs a version of Brocade Fabric OS or SANnav listed as vulnerable AND has SSH server enabled, with an RSA host key smaller than 2048 bits.
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 data2.1.17.4.28.2.1
Upgrade Brocade Fabric OS to v7.4.2h/v8.2.1c/v8.2.2/v9.0.0 or later, and Brocade SANnav to v2.1.1 or later, to use SSH keys meeting current cryptographic standards.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-15387 — 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-2020-15387 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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