Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker crash and reload a Cisco ASA device by abusing an established SSL/TLS connection. For executives, the business impact is service interruption on security infrastructure, not data theft or code execution based on the provided sources.
Executive priority
Treat as high priority where ASA devices protect critical connectivity or are reachable from untrusted networks. The main risk is outage of security infrastructure. Patch planning should be prompt, with change control aligned to redundancy and business continuity needs.
Technical view
CVE-2020-27124 affects Cisco Adaptive Security Appliance Software SSL/TLS handling. Improper error handling on established SSL/TLS connections can trigger an unexpected device reload, causing denial of service. CVSS 3.1 is 8.6 with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Organizations running Cisco ASA Software on devices that accept SSL/TLS connections may be exposed. Internet-facing or critical-path ASA deployments carry higher operational risk because a reload can interrupt firewall, VPN, or perimeter security availability.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires reaching the affected ASA SSL/TLS service and maintaining a connection long enough to send a malicious SSL/TLS message. No exploit maturity details are provided.
Researcher notes
The provided data supports a remote unauthenticated DoS condition, not confidentiality impact, integrity impact, or code execution. Affected version granularity is not included in the bundle, so validation depends on Cisco’s advisory and local ASA software inventory.
Mitigation direction
- Apply Cisco software updates that address this vulnerability.
- Use Cisco’s advisory to identify fixed releases for affected ASA versions.
- Do not rely on workarounds; Cisco states none address this vulnerability.
- Prioritize exposed or high-availability ASA devices for maintenance windows.
- Review redundancy and failover readiness before patch deployment.
Validation and detection
- Inventory Cisco ASA Software deployments and versions.
- Check each deployment against Cisco’s advisory and fixed-release guidance.
- Identify ASA devices accepting SSL/TLS connections from untrusted networks.
- Confirm patched software is installed after maintenance.
- Review monitoring for unexpected ASA reloads or availability events.
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
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2020-27124 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/RL:X/RC:X/E:X
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:H/RL:X/RC:X/E:X3.94Primary 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/RL:X/RC:X/E:X
Source materials
- CVE List V5 sourceCVE List V5
- cisco-sa-asa-ssl-dos-7uZWwSEyCVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sa-rv-routers-xss-K7Z5U6q3CVE reference
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-xss-bLZw4CtqCVE reference
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.