CVE intelligence and bounded remediation

CVE-2023-20269 — Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability

Critical CVSS 9.1 CISA KEV

A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or an authenticated, remote attacker to establish a clientless SSL VPN session with an unauthorized user. This vulnerability is due to improper separation of authentication, authorization, and accounting (AAA) between the remote access VPN feature and the HTTPS management and site-to-site VPN features. An attacker could exploit this vulnerability by specifying a default connection profile/tunnel group while conducting a brute force attack or while establishing a clientless SSL VPN session using valid credentials. A successful exploit could allow the attacker to achieve one or both of the following: Identify valid credentials that could then be used to establish an unauthorized remote access VPN session. Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier). Notes: Establishing a client-based remote access VPN tunnel is not possible as these…

Severity
Critical
CVSS
9.1 (3.1)
Published
2023-09-06
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-288, CWE-863

Affected products

  • cisco / adaptive_security_appliance_software / 9.8.1
  • cisco / adaptive_security_appliance_software / 9.8.1.5
  • cisco / adaptive_security_appliance_software / 9.8.1.7
  • cisco / adaptive_security_appliance_software / 9.8.2
  • cisco / adaptive_security_appliance_software / 9.8.2.8
  • cisco / adaptive_security_appliance_software / 9.8.2.14

Showing 6 representative product identities from 246 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.