Security readout for executives and security teams
Plain-English summary
This flaw can let anyone on the network reachability path send a malicious HTTPS request to vulnerable Cisco ASA or FTD devices and force a reload. The business impact is service interruption: firewall, VPN, or security gateway functions may drop while the device restarts.
Executive priority
Treat as high priority for perimeter and VPN infrastructure because exploitation can interrupt critical network access without authentication. Prioritize systems exposed to the internet or broad internal networks.
Technical view
CVE-2021-1573 is an unauthenticated remote denial-of-service issue in the ASA and FTD web services interface. Improper input validation while parsing HTTPS requests can trigger a device reload. CVSS 3.1 is 8.6, with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Organizations using Cisco ASA Software or Cisco FTD Software with reachable HTTPS web services are the relevant exposure group. The bundle does not provide affected version ranges, so exposure must be confirmed against Cisco's advisory and local device inventory.
Exploitation context
The source bundle describes remote unauthenticated exploitation by malicious HTTPS request causing device reload. It does not cite public exploit availability, observed exploitation, or CISA KEV listing; KEV status is false in the bundle.
Researcher notes
The bundle identifies CWE-121 and CWE-787, suggesting memory safety conditions around HTTPS request parsing. Version specificity and fixed-release details are not included in the supplied data; rely on Cisco's advisory for precise applicability.
Mitigation direction
- Check Cisco's advisory for affected releases and fixed software guidance.
- Prioritize remediation for internet-facing or untrusted-network reachable devices.
- Restrict HTTPS web services access to trusted networks where feasible.
- Monitor affected appliances for unexpected reloads or availability drops.
Validation and detection
- Inventory Cisco ASA and FTD devices and record software versions.
- Identify whether HTTPS web services are reachable from untrusted networks.
- Compare versions and configurations against Cisco's advisory.
- Review device uptime, reload history, and logs for unexplained restarts.
- After remediation, verify software version and service exposure posture.
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-121: 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 lookupCWE-787: 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-2021-1573 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
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asafdt-webvpn-dos-KSqJAKPACVE 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.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.