Email Security ApplianceApplication · Cisco
CVE-2020-3181
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 the malware detection functionality in Cisco Advanced Malware Protection (AMP) in Cisco AsyncOS Software for Cisco Email Security Appliances (ESAs) could allow an unauthenticated remote attacker to exhaust resources on an affected device. The vulnerability is due to insufficient control over system memory allocation. An attacker could exploit this vulnerability by sending a crafted email through the targeted device. A successful exploit could allow the attacker to cause an email attachment that contains malware to be delivered to a user and cause email processing delays.
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 · moderate confidenceA vulnerability in Cisco Advanced Malware Protection (AMP) malware detection in Cisco AsyncOS for Email Security Appliances allows an unauthenticated remote attacker to exhaust system memory by sending crafted emails. The insufficient control over memory allocation causes the malware detection to fail, allowing malicious email attachments to be delivered to users while causing email processing delays.
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
Email Security ApplianceApplication
< 13.0.0CVSS 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
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
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 Email Security Appliance versionLog into the ESA CLI and run the command 'version' or access the web interface and check System Administration > Software Update > Installed Version to retrieve the exact AsyncOS version numberAffected if The installed version is any version below 13.0.0 (for example, 12.5.x, 11.x, or earlier)
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Confirm AMP is enabledLog into the ESA web interface and navigate to Security Services > Advanced Malware Protection, or use the CLI command 'ampconfig' to verify the AMP feature is turned onAffected if AMP is enabled and the ESA version is below 13.0.0
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Check for memory exhaustion indicatorsMonitor system memory using the CLI command 'status' or 'show memory' from the ESA console, or check the Email Security Monitor dashboard for abnormally high memory usageAffected if Memory usage is persistently high or approaching exhaustion while processing email
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Inspect email processing queues for delaysRun the command 'mailq' or access the Message Tracking in the web interface to observe queued messages and processing times, particularly for emails with attachmentsAffected if Email queue backup or significant processing delays are observed for emails with attachments, especially after receiving external mail flow
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Review AMP scan failuresCheck the ESA logs or Message Tracking for AMP-related scan failures, timeouts, or errors using the CLI command 'grep -i "AMP" /var/log/ces/*' or through the web interface log entriesAffected if AMP scan failures are logged or attachments bypass malware scanning due to detection timeouts
You are affected if your Cisco Email Security Appliance runs any version below 13.0.0 with Advanced Malware Protection enabled, and you observe memory exhaustion or AMP scan failures when processing crafted email attachments.
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 data13.0.0
Apply the vendor-supplied software update when available. Until then, monitor email processing queues for delays and consider implementing additional email filtering or quarantine measures for high-risk attachments.
Fix this in Email Security Appliance
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 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 $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3181 — 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-2020-3181 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
- No spam, self-promotion, credentials, or personal data