Identity Services EngineApplication · Cisco
CVE-2020-3353
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 syslog processing engine of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a race condition that may occur when syslog messages are processed. An attacker could exploit this vulnerability by sending a high rate of syslog messages to an affected device. A successful exploit could allow the attacker to cause the Application Server process to crash, resulting in a DoS condition.
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 race condition exists in the syslog processing engine of Cisco Identity Services Engine (ISE). When an attacker sends a high volume of syslog messages to an affected device, the race condition triggers during message processing, causing the Application Server process to crash and resulting in a denial of service.
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
Identity Services EngineApplication
= 2.2.0.470= 2.3.0.298= 2.4.0.357CVSS 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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Confirm Cisco ISE is installedIdentify if Cisco Identity Services Engine is deployed in your environment. This is typically an appliance or VM running Cisco ISE software.Affected if The system is running Cisco Identity Services Engine software.
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Check installed Cisco ISE versionUse the Cisco ISE admin GUI or CLI command 'show version' to determine the exact version and build number of the installed Cisco ISE software.Affected if The installed version is exactly 2.2.0.470, 2.3.0.298, or 2.4.0.357.
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Verify syslog receiver is enabledIn Cisco ISE, navigate to Administration > System > Logging > Logging Categories or use the CLI command 'show logging' to check if syslog message reception is enabled.Affected if Syslog logging is enabled and the device is configured to receive syslog messages from network sources.
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Check syslog configuration for rate limitingReview the syslog configuration in Cisco ISE under Administration > System > Logging > Remote Logging Targets to see if any rate limiting or throttling is configured.Affected if No syslog rate limiting is configured and the device accepts syslog traffic from untrusted or unauthenticated sources.
You are affected if you are running Cisco ISE versions 2.2.0.470, 2.3.0.298, or 2.4.0.357 with syslog reception enabled and no rate limiting protection.
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 the Cisco ISE security patch when available. As an interim measure, consider implementing syslog traffic rate limiting or network segmentation to reduce exposure to unauthenticated syslog traffic.
Fix this in Identity Services Engine
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing5.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3353 — 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-2020-3353 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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