Security readout for executives and security teams
Plain-English summary
CVE-2020-3572 can let an unauthenticated remote attacker exhaust memory on Cisco ASA or FTD devices by abusing SSL/TLS session handling. The result is denial of service for new SSL/TLS connections, and recovery requires manual intervention.
Executive priority
Treat this as high priority for internet-facing VPN, firewall, or remote-access infrastructure because outage impact can be immediate and recovery is manual. Prioritize confirmation of affected Cisco devices and vendor-guided remediation.
Technical view
The flaw is a memory leak in the SSL/TLS session handler when closing connections in a specific state. Repeated SSL/TLS sessions can consume device memory, preventing new SSL/TLS processing. The provided CVSS is 8.6, driven by network reachability, no authentication, low complexity, and high availability impact.
Likely exposure
Organizations using Cisco ASA or FTD Software with exposed SSL/TLS services are the likely exposure group. The provided bundle does not specify affected versions, configurations, or fixed releases.
Exploitation context
The bundle does not state active exploitation, and KEV status is false. Exploitation requires remote SSL/TLS reachability and repeated session activity, but no authentication or user interaction.
Researcher notes
Evidence supports unauthenticated remote DoS via memory exhaustion, not code execution or data compromise. Version details and fixes are not included in the bundle, so validation depends on the Cisco advisory.
Mitigation direction
- Review Cisco advisory for affected releases, fixed software, and Cisco-stated workarounds.
- Plan maintenance to update affected ASA or FTD devices per Cisco guidance.
- Monitor device memory and SSL/TLS service health until remediation is confirmed.
- Prepare manual recovery procedures because successful exploitation requires manual intervention to recover.
Validation and detection
- Inventory Cisco ASA and FTD deployments that expose SSL/TLS services.
- Compare running software versions and configurations against Cisco’s advisory.
- Check logs and telemetry for memory exhaustion or SSL/TLS connection failures.
- Confirm remediation by verifying vendor-recommended fixed software or mitigation status.
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
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CWE-400: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-3572 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 8.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
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:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20201021 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SSL/TLS Session Denial of Service 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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.