Known exploited · Cisco
CVE-2023-20269: Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability
What it is
Cisco Adaptive Security Appliance and Firepower Threat Defense contain an unauthorized access vulnerability that could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or establish a clientless SSL VPN session with an unauthorized user.
- Vendor
- Cisco
- Product
- Adaptive Security Appliance and Firepower Threat Defense
- Added to KEV
- September 13, 2023
- CISA due date
- October 4, 2023
- Ransomware use
- Known
What CISA requires
Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.
Forensic triage
No
What to do now
- Find every instance of Adaptive Security Appliance and Firepower Threat Defense you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before October 4, 2023 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
References
H2 Security
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Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.