Security readout for executives and security teams
Plain-English summary
This Cisco VPN weakness can help remote attackers test stolen or guessed credentials and, in some older ASA releases, open an unauthorized browser-based VPN session using valid credentials. It does not bypass authentication or MFA, but CISA lists it as exploited in the wild, increasing its practical urgency.
Executive priority
Treat affected internet-reachable VPN gateways as a high-priority remediation item because CISA confirms exploitation. Patch promptly or apply Cisco’s workaround, confirm MFA coverage, and investigate suspicious authentication activity. The vulnerability is constrained by its need for valid credentials to establish a session, but credential discovery can enable subsequent unauthorized VPN access.
Technical view
Improper separation of AAA processing among remote-access VPN, HTTPS management, and site-to-site VPN features permits abuse of a default connection profile or tunnel group. An unauthenticated attacker may identify valid credential combinations through brute force. An authenticated attacker may establish an unauthorized clientless SSL VPN session on ASA 9.16 or earlier. Client-based VPN tunnels cannot be established through this flaw.
Likely exposure
Exposure is highest on network-reachable Cisco ASA or FTD devices running listed affected versions with remote-access VPN enabled. ASA 9.16 or earlier also faces the clientless SSL VPN session risk. Successful session establishment still requires valid credentials and any configured second factor.
Exploitation context
CISA’s Known Exploited Vulnerabilities catalog supports active exploitation in the wild. The supplied sources do not establish exploitation prevalence, named targets, or specific campaign attribution. Although the CVSS score is 5.0, external VPN exposure and confirmed exploitation justify elevated operational priority.
Researcher notes
CWE-288 applies. The key distinction is that unauthenticated activity can facilitate credential identification, while unauthorized clientless session establishment requires valid credentials and is limited to ASA 9.16 or earlier. Authentication is not bypassed, configured MFA remains required, and this flaw cannot create a client-based remote-access tunnel because default profiles lack configurable IP pools.
Mitigation direction
- Apply the appropriate Cisco software update identified in the vendor advisory.
- If immediate updating is impossible, implement Cisco’s documented workaround exactly as specified.
- Require MFA for remote-access VPN accounts and verify it cannot be bypassed through alternate profiles.
- Monitor exposed VPN services for repeated authentication failures and unexpected clientless sessions.
Validation and detection
- Inventory Cisco ASA and FTD versions and identify systems with remote-access VPN enabled.
- Compare each deployed release against Cisco’s affected and fixed-release information.
- Review default connection profiles and tunnel groups for unintended authentication or authorization paths.
- Check authentication records for repeated failures followed by successful VPN access.
- Confirm MFA is enforced for every applicable remote-access VPN account.
- On ASA 9.16 or earlier, review clientless SSL VPN sessions for unauthorized access.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-288: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2023-20269 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N3.11.4ciscoVulnerability scoring details
Base CVSS 3.1 score
5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2023-20269 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2023-09-13T00:00:00.000Z: CVE-2023-20269 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- cisco-sa-asaftd-ravpn-auth-8LyfCkeCCVE reference, cisco
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-20269CVE reference, CISA-ADP · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Authentication Bypass Using an Alternate Path or Channel
Authentication Bypass Using an Alternate Path or Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.