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Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2023-20245

MEDIUM · 5.8 CVSS v3.1 Published 2023-11-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
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 the per-user-override feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured access control list (ACL) and allow traffic that should be denied to flow through an affected device. These vulnerabilities are due to a logic error that could occur when the affected software constructs and applies per-user-override rules. An attacker could exploit these vulnerabilities by connecting to a network through an affected device that has a vulnerable configuration. A successful exploit could allow the attacker to bypass the interface ACL and access resources that would should be protected.

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-2023-20245 is a logic error vulnerability in the per-user-override feature of Cisco ASA and FTD firewalls. When the software constructs and applies per-user-override rules, it can incorrectly bypass interface ACLs, allowing traffic that should be denied to pass through the affected device. An unauthenticated remote attacker on the internal network can exploit this by connecting through the vulnerable device.

MitigationApply Cisco security updates for ASA and FTD software. Until patches are available, audit per-user-override configurations and consider disabling the feature if not required, while implementing additional network segmentation as compensating control.

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:= 9.8.3.14= 9.8.3.16= 9.8.3.18= 9.8.3.21= 9.8.3.26= 9.8.3.29= 9.8.4= 9.8.4.3= 9.8.4.7= 9.8.4.8= 9.8.4.10= 9.8.4.12
Secure Firewall Threat DefenseApplication
Affected:= 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= 6.2.3.12= 6.2.3.13= 6.2.3.14

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
Changed
Confidentiality
None
Integrity
Low
Availability
None

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

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 Cisco ASA or FTD software version
    Run 'show version' on the ASA CLI or 'show version' on FTD via CLI (admin@ftd). Note the full software version string.
    Affected if The version matches any of: ASA 9.8.3.14, 9.8.3.16, 9.8.3.18, 9.8.3.21, 9.8.3.26, 9.8.3.29, 9.8.4, 9.8.4.3, 9.8.4.7, 9.8.4.8, 9.8.4.10, 9.8.4.12 OR FTD 6.2.3.3 through 6.2.3.14.
  2. Confirm the per-user-override feature is configured
    Run 'show run per-user-override' or 'show running-config | include per-user-override' in the ASA/FTD CLI. Also check for any AAA commands related to user-based policies such as 'user-domain' or 'user-authentication' under the relevant interface configurations.
    Affected if Per-user-override is enabled or any user-based AAA authentication/authorization policies are active on the device.
  3. Verify that per-user-override rules exist
    Run 'show per-user-override rule' or examine the configuration for per-user-override rule definitions. Check if there are any user-specific ACL mappings configured via 'access-list per-user' commands.
    Affected if Any per-user-override rules or user-specific ACL entries are defined in the configuration.
  4. Review interface ACL configurations
    Run 'show access-list' or 'show running-config access-list' to review the interface ACLs applied via 'access-group' commands. Identify which interfaces have ACLs applied and note their permit/deny entries.
    Affected if Interface ACLs are applied to any interface (via access-group) AND per-user-override is configured, creating the condition where ACL bypass may occur.

The device is affected if it runs a listed ASA or FTD version AND has per-user-override configured with active user-specific rules, regardless of whether interface ACLs are present.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Cisco security updates for ASA and FTD software. Until patches are available, audit per-user-override configurations and consider disabling the feature if not required, while implementing additional network segmentation as compensating control.

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2023-20245 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
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  • Version or environment caveats, and links to real fixes
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