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Secure Firewall Threat DefenseApplication · Cisco

CVE-2021-1445

HIGH · 7.5 CVSS v3.1 Published 2021-04-29
Fix available
A fix is available. Upgrade to 6.6.4 / 6.7.0.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Multiple vulnerabilities in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to lack of proper input validation of the HTTPS request. An attacker could exploit these vulnerabilities by sending a crafted HTTPS request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CVE-2021-1445 is a vulnerability in Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) software stemming from improper input validation of HTTPS requests. An unauthenticated remote attacker can send a crafted HTTPS request to an affected device with specific AnyConnect or WebVPN configurations, causing the device to reload and resulting in a denial of service condition.

MitigationApply the relevant Cisco security updates (refer to Cisco advisory) and, if暂时 unable to patch, restrict VPN access to trusted sources or disable affected AnyConnect/WebVPN features if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Secure Firewall Threat DefenseApplication
Affected:>= 6.5.0, < 6.6.4>= 6.7.0, < 6.7.0.1
Adaptive Security Appliance SoftwareOperating system
Affected:>= 9.7, < 9.8.4.34>= 9.9, < 9.9.2.85>= 9.10, < 9.12.4.13>= 9.13, < 9.13.1.21>= 9.14, < 9.14.2.8>= 9.15, < 9.15.1.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed product and version
    Log into the device CLI and run 'show version' to display the system software version and product type (ASA or FTD). Look for the version number in the output.
    Affected if The version falls within any of the affected ranges: FTD >= 6.5.0 < 6.6.4 or >= 6.7.0 < 6.7.0.1; ASA >= 9.7 < 9.8.4.34, >= 9.9 < 9.9.2.85, >= 9.10 < 9.12.4.13, >= 9.13 < 9.13.1.21, >= 9.14 < 9.14.2.8, or >= 9.15 < 9.15.1.7
  2. Check if AnyConnect VPN is enabled
    Run 'show running-config' and search for 'anyconnect' or use 'show vpn-sessiondb' to see active AnyConnect sessions. Also check the configuration for 'webvpn' which may indicate WebVPN is configured.
    Affected if AnyConnect or WebVPN configuration is present in the running configuration (the device must have one of these features configured for the vulnerability to be exploitable)
  3. Verify the HTTPS listener configuration
    Run 'show running-config http' to see if HTTP server is enabled, and check 'show webvpn' to confirm WebVPN is active. The vulnerability is triggered via crafted HTTPS requests to the affected device.
    Affected if HTTP server is enabled for VPN access or WebVPN is actively configured

The device is affected if it runs a vulnerable ASA or FTD version AND has AnyConnect or WebVPN features configured, allowing an unauthenticated attacker to trigger a denial of service via crafted HTTPS requests.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 6.6.4 / 6.7.0.1 / 9.8.4.34 or later
Fixed in 6.6.46.7.0.19.8.4.34
Interim mitigation

Apply the relevant Cisco security updates (refer to Cisco advisory) and, if暂时 unable to patch, restrict VPN access to trusted sources or disable affected AnyConnect/WebVPN features if not required.

Fix this in Secure Firewall Threat Defense Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,620
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-1445 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data