Secure Firewall Threat DefenseApplication · Cisco
CVE-2020-3533
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 Simple Network Management Protocol (SNMP) input packet processor of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly. The vulnerability is due to a lack of sufficient memory management protections under heavy SNMP polling loads. An attacker could exploit this vulnerability by sending a high rate of SNMP requests to the SNMP daemon through the management interface on an affected device. A successful exploit could allow the attacker to cause the SNMP daemon process to consume a large amount of system memory over time, which could then lead to an unexpected device restart, causing a denial of service (DoS) condition. This vulnerability affects all versions of SNMP.
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 memory management vulnerability in the SNMP input packet processor of Cisco Firepower Threat Defense (FTD) allows an unauthenticated remote attacker to cause denial of service by sending a high rate of SNMP requests through the management interface, leading to excessive memory consumption by the SNMP daemon and unexpected device restarts.
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
Secure Firewall Threat DefenseApplication
< 6.3.0.6>= 6.4.0, < 6.4.0.10>= 6.5.0, < 6.5.0.5>= 6.6.0, < 6.6.1CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/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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Confirm Cisco FTD is deployedIdentify the device type by checking 'show version' output or system documentation - look for 'Cisco Firepower Threat Defense' or 'FTD' in the device identificationAffected if The device is not Cisco Firepower Threat Defense (the vulnerability only affects FTD)
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Check installed FTD software versionRun 'show version' on the FTD CLI or check the FTD management center - locate the software version string (e.g., 6.4.0.5)Affected if The installed version falls into any of these ranges: < 6.3.0.6, >= 6.4.0 and < 6.4.0.10, >= 6.5.0 and < 6.5.0.5, >= 6.6.0 and < 6.6.1
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Verify SNMP is enabled on the management interfaceRun 'show snmp-server' or 'show running-config snmp' in FTD CLI - check if SNMP is configured and which interface(s) are bound to SNMP accessAffected if SNMP is enabled and listening on the management interface (the vulnerability is triggered via SNMP requests to the management interface)
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Assess management interface exposureReview the network configuration - check if the management interface IP is reachable from untrusted networks, review ACLs applied to management interface, verify management access list entriesAffected if The management interface with SNMP is reachable from untrusted or external networks (exposing the device to unauthenticated SNMP attackers)
You are affected if you run vulnerable FTD versions AND have SNMP enabled on an accessible management interface, because an attacker sending high-rate SNMP requests to the management interface can trigger memory exhaustion and device restarts.
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 data6.3.0.66.4.0.106.5.0.5
Apply the Cisco FTD software update/patch when available; meanwhile, restrict access to the management interface via ACLs or network segmentation to limit SNMP exposure to trusted sources.
Fix this in Secure Firewall Threat Defense
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 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 $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3533 — 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-2020-3533 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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- Version or environment caveats, and links to real fixes
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