Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker exhaust memory on Cisco ASA or FTD devices by sending crafted fragmented IP traffic. The business impact is service disruption: the device may stop processing traffic and could require a manual reboot.
Executive priority
Treat as high priority for perimeter firewalls and VPN/security gateways because successful exploitation can interrupt traffic flow. Prioritize externally exposed ASA and FTD assets first, then internal high-availability chokepoints.
Technical view
CVE-2020-3373 is an IP fragment reassembly memory leak in Cisco ASA Software and FTD Software. Improper error handling during specific fragment reassembly failures can continuously consume memory. It affects IPv4 and IPv6 traffic and is rated CVSS 8.6 for high availability impact.
Likely exposure
Exposure is most relevant for Cisco ASA or FTD devices that process untrusted IPv4 or IPv6 traffic. The source bundle does not provide exact affected release ranges, so teams must confirm exposure against Cisco's advisory.
Exploitation context
The bundle describes remote, unauthenticated exploitation using crafted fragmented IP traffic. It does not cite CISA KEV listing or other evidence of active exploitation, so active exploitation should not be assumed from these sources.
Researcher notes
The source maps this to CWE-400 resource consumption. The key technical condition is improper error handling during IP fragment reassembly failure. Exact affected versions and fixed releases are not present in the bundle; rely on Cisco's advisory for those details.
Mitigation direction
- Identify Cisco ASA and FTD devices in internet-facing and perimeter roles.
- Check Cisco's advisory for affected releases and vendor-recommended fixes.
- Upgrade or apply Cisco-recommended mitigation after confirming device applicability.
- Monitor memory usage and traffic processing health until remediation is complete.
- Prepare operational reboot procedures for affected devices if DoS symptoms appear.
Validation and detection
- Compare deployed ASA and FTD versions against Cisco advisory applicability.
- Confirm whether devices process untrusted IPv4 or IPv6 fragmented traffic.
- Review monitoring for abnormal memory growth or traffic processing failures.
- Verify remediation status after upgrade or vendor-guided mitigation.
- Document remaining devices where version exposure is still unknown.
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-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 lookupCVE-2020-3373 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
- 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 IP Fragment Memory Leak 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.
