CVE-2023-20269: Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-08 00:03 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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 default connection profiles/tunnel groups do not and cannot have an IP address pool configured. This vulnerability does not allow an attacker to bypass authentication. To successfully establish a remote access VPN session, valid credentials are required, including a valid second factor if multi-factor authentication (MFA) is configured. Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability.
Description quoted from the CVE record (assigned by cisco, published 2023-09-06).
Weakness: Authentication Bypass Using an Alternate Path or Channel
How it can be exploited
Exploitable over the network with low attack complexity needing low privileges and no user interaction. Impact: confidentiality none, integrity low, availability none. CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: partial.
- On CISA KEV since
- 2023-09-13
- US federal deadline
- 2023-10-04
- Ransomware use
- Yes
Public exploit evidence (Exploit Observer)
Exploit Observer found 1 research write-up naming this CVE.
See all 7 references on Exploit Observer
Live scores
- EPSS
- 0.266
likely to be attacked soon - VEDAS
- 0.726
likely exploited - On CISA KEV
- Yes, since 2023-09-13
- Detection rule
- No public rule yet
Thin horizontal line: the “likely exploited” threshold (EPSS 0.10, VEDAS 0.5). Shaded “no data” areas are periods when cve-scores did not publish.
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Cisco Adaptive Security Appliance (ASA) Software | version 9.8.1 version 9.8.1.5 version 9.8.1.7 version 9.8.2 version 9.8.2.8 version 9.8.2.14 version 9.8.2.15 version 9.8.2.17 and 162 more ranges | Not stated |
| Cisco Firepower Threat Defense Software | version 6.2.3 version 6.2.3.1 version 6.2.3.2 version 6.2.3.3 version 6.2.3.4 version 6.2.3.5 version 6.2.3.6 version 6.2.3.7 and 68 more ranges | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
CISA required action: Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.
Vendor guidance:
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC
- https://nvd.nist.gov/vuln/detail/CVE-2023-20269
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
- CISA, FBI and partners warn SafePay ransomware has hit at least 600 critical-infrastructure victims (full advisory)
References
Government sources
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-20269 (government-resource)
Other references
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
Supporting partners
