Cloud Email SecurityApplication · Cisco
CVE-2020-3132
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 email message scanning feature of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a temporary denial of service (DoS) condition on an affected device. The vulnerability is due to inadequate parsing mechanisms for specific email body components. An attacker could exploit this vulnerability by sending a malicious email containing a high number of shortened URLs through an affected device. A successful exploit could allow the attacker to consume processing resources, causing a DoS condition on an affected device. To successfully exploit this vulnerability, certain conditions beyond the control of the attacker must occur.
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 vulnerability in Cisco Email Security Appliance's AsyncOS email message scanning feature allows unauthenticated remote attackers to cause denial of service by sending emails containing a high number of shortened URLs. The inadequate parsing mechanisms for email body components consume excessive processing resources when scanning these malicious emails.
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
Cloud Email SecurityApplication
< 12.5.1-037< 13.0.0-375
Email Security ApplianceApplication
< 12.5.1-037< 13.0.0-375CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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 product typeDetermine if your environment uses Cisco Email Security Appliance (ESA) hardware/virtual appliance or Cisco Cloud Email Security service. This affects which version applies.Affected if Using either product type but version is unknown or unverified
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Check installed AsyncOS versionLog into the ESA CLI and run the 'version' command, or check the Cloud Email Security dashboard for the current AsyncOS version number.Affected if Version is below 12.5.1-037 OR below 13.0.0-375
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Verify email message scanning is enabledIn the ESA web interface, go to Incoming Mail Policies or Message Filters to confirm email body scanning is active. The vulnerability affects the scanning engine when processing URLs.Affected if Email message scanning is enabled and version is in the affected range
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Confirm URL scanning processingCheck URL filtering or content filter settings in the ESA: Go to Mail Policies > Incoming Content Filters or URL Filtering to see if shortened URL processing or URL rewriting is configured.Affected if URL scanning/filtering is active and version is vulnerable
Your environment is affected if you are running Cisco ESA or Cloud Email Security with AsyncOS version below 12.5.1-037 or below 13.0.0-375 and email/URL scanning is enabled.
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 data12.5.1-03713.0.0-375
Apply Cisco's available software updates for AsyncOS. Additionally, implement URL filtering policies or rate limiting on shortened URL processing to mitigate exploitation while patches are being deployed.
Fix this in Cloud Email Security
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3132 — 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-2020-3132 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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