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CVE Record

CVE-2020-3285: Cisco Firepower Threat Defense Software SSL/TLS URL Category Bypass Vulnerability

A vulnerability in the Transport Layer Security version 1.3 (TLS 1.3) policy with URL category functionality for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured TLS 1.3 policy to block traffic for a specific URL. The vulnerability is due to a logic error with Snort handling of the connection with the TLS 1.3 policy and URL category configuration. An attacker could exploit this vulnerability by sending crafted TLS 1.3 connections to an affected device. A successful exploit could allow the attacker to bypass the TLS 1.3 policy and access URLs that are outside the affected device and normally would be dropped.

MediumCVSS 5.8Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw lets an unauthenticated remote actor bypass certain Cisco FTD URL blocking rules when TLS 1.3 and URL category policy are configured together. It does not let them take over the device, but it can weaken web access controls.

Executive priority

Treat as a control-bypass issue, not a firewall takeover. Prioritize verification where Cisco FTD URL filtering is a relied-upon business or compliance control.

Technical view

Cisco describes a logic error in Snort handling for TLS 1.3 policy plus URL category configuration in Firepower Threat Defense Software. Crafted TLS 1.3 connections could bypass policy enforcement for URLs that should be dropped. CVSS v3.0 is 5.8.

Likely exposure

Exposure is most likely on Cisco FTD deployments using TLS 1.3 policy with URL category blocking. The provided sources do not identify affected version ranges, so inventory confirmation needs Cisco advisory review.

Exploitation context

The bundle indicates unauthenticated remote exploitation is possible with crafted TLS 1.3 connections. It does not show CISA KEV listing or cited evidence of active exploitation.

Researcher notes

CWE-693 fits protection-mechanism failure. The source bundle lacks affected version ranges and concrete fixed releases, so avoid over-scoping until Cisco advisory details are confirmed.

Mitigation direction

  • Review Cisco advisory cisco-sa-ssl-bypass-O5tGum2n for affected releases and vendor remediation.
  • Identify FTD devices using TLS 1.3 policy with URL category blocking.
  • Apply Cisco-recommended software updates or configuration guidance when confirmed applicable.
  • Prioritize systems where URL filtering enforces compliance, acceptable-use, or threat-control requirements.

Validation and detection

  • Inventory Cisco Firepower Threat Defense deployments and software versions.
  • Check whether TLS 1.3 policy and URL category functionality are enabled together.
  • Confirm vendor advisory applicability against each deployed release.
  • Review policy logs for unexpected access to URLs that should be blocked.
Prepared
Confidence
medium
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-693: Exact CWE lookup

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cve · low confidence lookup

CVE-2020-3285 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.8 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.8CVSS 3.0MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

5.8Medium
CVSS 3.0 vector shape for CVE-2020-3285Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Firepower Threat Defense Softwaren/aListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-693 · source CWE mapping

Protection Mechanism Failure

Protection Mechanism Failure represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.