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Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2024-20408

HIGH · 7.7 CVSS v3.1 Published 2024-10-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable 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
A vulnerability in the Dynamic Access Policies (DAP) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly. To exploit this vulnerability, an attacker would need valid remote access VPN user credentials on the affected device. This vulnerability is due to improper validation of data in HTTPS POST requests. An attacker could exploit this vulnerability by sending a crafted HTTPS POST request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

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

This vulnerability exists in the Dynamic Access Policies (DAP) feature of Cisco ASA and FTD software. It stems from improper validation of data within HTTPS POST requests. An attacker with valid remote access VPN credentials can send a crafted HTTPS POST request to trigger an unexpected device reload, causing denial of service.

MitigationApply the relevant Cisco security update/patch for ASA or FTD software as provided in the Cisco security advisory. Ensure valid VPN credentials are reviewed and rotated if compromised.

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
Adaptive Security Appliance SoftwareOperating system
Affected:= 9.8.1= 9.8.1.5= 9.8.1.7= 9.8.2= 9.8.2.8= 9.8.2.14= 9.8.2.15= 9.8.2.17= 9.8.2.20= 9.8.2.24= 9.8.2.26= 9.8.2.28
Secure Firewall Threat DefenseApplication
Affected:= 6.2.3= 6.2.3.1= 6.2.3.2= 6.2.3.3= 6.2.3.4= 6.2.3.5= 6.2.3.6= 6.2.3.7= 6.2.3.8= 6.2.3.9= 6.2.3.10= 6.2.3.11

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
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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 device product and version
    On Cisco ASA, run 'show version' or 'show running-config | include version' to get the software version. On FTD, access the CLI via 'expert' then 'sudo su -' and run 'show version' or check via FMC/Ftdcli.
    Affected if The version matches one of the affected versions listed: ASA 9.8.1 through 9.8.2.28 (specific builds: 9.8.1, 9.8.1.5, 9.8.1.7, 9.8.2, 9.8.2.8, 9.8.2.14, 9.8.2.15, 9.8.2.17, 9.8.2.20, 9.8.2.24, 9.8.2.26, 9.8.2.28) or FTD 6.2.3 through 6.2.3.11.
  2. Verify if Dynamic Access Policies (DAP) feature is configured
    On ASA, run 'show dap trace' or 'show running-config dap' to check if any DAP policies are defined. On FTD, check via FMC under Remote Access VPN > Dynamic Access Policies, or run 'show dap' in FTD CLI.
    Affected if Any DAP policy is actively configured or enabled on the device.
  3. Confirm remote access VPN is enabled
    Run 'show vpn-sessiondb' or 'show running-config | include vpn' on ASA/FTD to check for active remote access VPN configurations such as SSL VPN or AnyConnect.
    Affected if Remote access VPN (AnyConnect SSL VPN or clientless SSL VPN) is configured and operational.
  4. Review device reload history for unexplained restarts
    Run 'show reload' or 'show crashinfo' on ASA. On FTD, check 'show system reboot history' or review logs via FMC for unexpected device reloads that were not initiated by an administrator.
    Affected if Device has experienced unexplained reloads or crashes, especially during periods when legitimate VPN activity occurred.

Your device is likely affected if it runs an affected ASA or FTD version (9.8.x or 6.2.3.x), has Dynamic Access Policies (DAP) enabled, and has remote access VPN configured, as all three conditions are required for this vulnerability to be exploitable.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the relevant Cisco security update/patch for ASA or FTD software as provided in the Cisco security advisory. Ensure valid VPN credentials are reviewed and rotated if compromised.

Recommended fix Moderate confidence

Upgrade to Cisco ASA 9.8.3 or later / FTD 6.2.3.4 or later (verify exact releases in Cisco Security Advisory)

  1. 1. Identify the current Cisco ASA or FTD software version running on the affected device using 'show version'
  2. 2. Review the Cisco Security Advisory (cisco-sa-asaftd-https-post-dos-XXXXXXX) on sec.cloudapps.cisco.com for the specific fixed software releases
  3. 3. Download the recommended fixed version from Cisco Software Download center
  4. 4. Plan maintenance window as the upgrade will require device reload
  5. 5. Back up current device configuration
  6. 6. Upload and install the fixed software version using 'software install' or through the device manager for FTD
  7. 7. Verify the device reloads and comes up with the new version using 'show version'
  8. 8. Confirm the DAP feature functions correctly with test remote access VPN connection
Caveat Software upgrade may cause configuration compatibility issues; test in staging environment first; requires device reload causing temporary service interruption

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2024-20408 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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