Ios Rom MonitorOperating system · Cisco
CVE-2018-15370
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 · uneditedA vulnerability in Cisco IOS ROM Monitor (ROMMON) Software for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, local attacker to bypass Cisco Secure Boot validation checks and load a compromised software image on an affected device. The vulnerability is due to the presence of a hidden command in the affected software. An attacker could exploit this vulnerability by connecting to an affected device via the console, forcing the device into ROMMON mode, and writing a malicious pattern to a specific memory address on the device. A successful exploit could allow the attacker to bypass signature validation checks by Cisco Secure Boot technology and load a compromised software image on the affected device. A compromised software image is any software image that has not been digitally signed by Cisco.
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 confidenceA hidden command in Cisco IOS ROMMON firmware for Catalyst 6800 Series Switches allows an attacker with console access to write a malicious pattern to a specific memory address, bypassing Cisco Secure Boot signature validation and loading unsigned software.
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
Ios Rom MonitorOperating system
= 15.1\(2\)sy3CVSS 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
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 device modelUse 'show version' or physically inspect the chassis to confirm it is a Cisco Catalyst 6800 Series SwitchAffected if Device is NOT a Catalyst 6800 Series Switch - the vulnerability does not apply
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Check the ROMMON firmware versionAccess the ROMMON prompt via console and run the version command, or use 'show rom-monitor' from IOS. Compare the displayed version against 15.1(2)sy3Affected if ROMMON version equals exactly 15.1(2)sy3 - this is the only affected version listed
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Verify console access exposureAudit physical security of console ports and review access logs for any unauthorized ROMMON access attempts. Check if console cabling is controlled and if weak or default console passwords are in useAffected if Console port is accessible to untrusted users - console access is required to exploit this flaw
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Check for unsigned software loadingAfter suspected exploitation, use 'show version' and 'show boot' to inspect loaded images. Verify if any unsigned or untrusted software images were loaded outside the normal Secure Boot chainAffected if Unsigned software is running or was loaded - this indicates successful exploitation of the Secure Boot bypass
A user is affected if they own a Catalyst 6800 Series Switch with ROMMON version exactly 15.1(2)sy3 and an attacker has console access to the device.
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 dataApply Cisco-provided ROMMON firmware updates to remove the hidden command; restrict physical access to console ports and monitor for unauthorized ROMMON access.
Fix this in Ios Rom Monitor
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-15370 — 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-2018-15370 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
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