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CVE Record

CVE-2020-3196: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SSL/TLS Denial of Service Vulnerability

A vulnerability in the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust memory resources on the affected device, leading to a denial of service (DoS) condition. The vulnerability is due to improper resource management for inbound SSL/TLS connections. An attacker could exploit this vulnerability by establishing multiple SSL/TLS connections with specific conditions to the affected device. A successful exploit could allow the attacker to exhaust the memory on the affected device, causing the device to stop accepting new SSL/TLS connections and resulting in a DoS condition for services on the device that process SSL/TLS traffic. Manual intervention is required to recover an affected device.

HighCVSS 8.6Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-3196 can let a remote unauthenticated attacker consume memory on Cisco ASA and FTD devices handling SSL/TLS traffic. Successful exploitation can stop new SSL/TLS connections and require manual recovery, creating business risk for VPN, access, or security gateway availability.

Executive priority

Treat as high priority for internet-facing or business-critical Cisco edge devices. The main risk is service outage, not data theft, but outage recovery may require manual action and can affect remote access or security gateway availability.

Technical view

The flaw is improper resource management in the SSL/TLS handler, mapped to CWE-400. Multiple inbound SSL/TLS connections under specific conditions can exhaust device memory. CVSS v3.0 is 8.6 high with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.

Likely exposure

Exposure is most relevant where Cisco ASA or FTD devices accept SSL/TLS traffic from untrusted networks. The source bundle does not provide affected or fixed version ranges, so device inventory must be matched against Cisco guidance.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. It does support remote unauthenticated denial of service with manual intervention required after successful exploitation.

Researcher notes

Evidence is limited to the CVE record and Cisco advisory reference. Do not assume specific fixed releases, exploit availability, or product versions beyond Cisco ASA and FTD named in the description. Focus validation on SSL/TLS exposure and memory exhaustion symptoms.

Mitigation direction

  • Review Cisco’s advisory for affected and fixed software releases.
  • Upgrade or apply Cisco-recommended mitigations only after confirming applicability.
  • Limit unnecessary SSL/TLS exposure to untrusted networks where operationally possible.
  • Ensure recovery runbooks cover manual intervention for affected devices.

Validation and detection

  • Inventory Cisco ASA and FTD devices processing SSL/TLS traffic.
  • Compare running versions against Cisco’s advisory.
  • Check monitoring for memory exhaustion or rejected SSL/TLS connections.
  • Review incident history for unexplained SSL/TLS service outages.
Prepared
Confidence
high
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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-400: 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 lookup
cve · low confidence lookup

CVE-2020-3196 mapping review

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

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.0)
Known Exploited
No
Published

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

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
8.6CVSS 3.0HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

8.6High
CVSS 3.0 vector shape for CVE-2020-3196Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Adaptive Security Appliance (ASA) Softwaren/aListed
Weakness

CWE details

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

CWE-400 · source CWE mapping

Uncontrolled Resource Consumption

Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.