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.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-693: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-3285 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- 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
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.8MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20200506 Cisco Firepower Threat Defense Software SSL/TLS URL Category Bypass VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Protection Mechanism Failure
Protection Mechanism Failure represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
