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CriticalCISA KEVExploited in the wildPublic exploit

Unauthorized Access in Cisco ASA/FTD Remote Access VPN

IdentifiersCVE-2023-20269CWE-288· Authentication Bypass Using an…

CVE-2023-20269 is an unauthorized access vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. The flaw is caused by 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 can exploit the issue by specifying a default connection profile/tunnel group during authentication attempts. This enables an unauthenticated remote attacker to conduct brute-force attacks to identify valid username and password combinations, and it enables an authenticated remote attacker using valid credentials to establish a clientless SSL VPN session as an unauthorized user. Cisco notes that the issue does not bypass authentication; valid credentials are still required to establish a VPN session, including a valid second factor where MFA is configured. On Cisco ASA Software Release 9.16 or earlier, successful exploitation can also result in establishment of a clientless SSL VPN session. Client-based remote access VPN tunnel establishment is not possible through these default connection profiles/tunnel groups because they do not and cannot have an IP address pool configured.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow attackers to enumerate valid VPN credentials through remote brute-force activity and then use those credentials to gain unauthorized remote access. In affected Cisco ASA releases 9.16 or earlier, an attacker with valid credentials may establish a clientless SSL VPN session as an unauthorized user. The vulnerability therefore increases the likelihood of initial access into enterprise environments, especially where VPN services are internet-exposed and MFA is absent or inconsistently enforced. The flaw does not itself bypass authentication or MFA, but it materially weakens access controls by exposing an alternate path that can be abused for credential validation and unauthorized session establishment.

Mitigation

If you can’t patch tonight, do this now.

Where immediate patching is not possible, apply Cisco-provided workarounds for CVE-2023-20269. The supplied content specifically notes mitigations including use of Dynamic Access Policies (DAP), adjusting vpn-simultaneous-logins settings, and restricting LOCAL user database access. Independently of vendor workarounds, enforce MFA on all VPN access, restrict exposure of remote access VPN services where feasible, monitor for password spraying and brute-force behavior against VPN endpoints, and disable or tightly control unnecessary clientless SSL VPN access. Evidence in the provided reporting indicates organizations with properly configured MFA were not observed to suffer successful Akira intrusions via this path.

Remediation

Patch, then assume compromise.

Cisco indicated that software updates would be released to address this vulnerability. Organizations should upgrade Cisco ASA and Cisco FTD to vendor-fixed releases as provided by Cisco for the affected product train. Because the issue is tied to AAA handling between remote access VPN and other features, remediation should include applying Cisco’s official fixes rather than relying solely on operational controls. After patching, organizations should review VPN authentication logs for evidence of brute-force attempts, credential abuse, or unexpected clientless SSL VPN sessions, and rotate potentially exposed credentials where compromise is suspected.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Cisco SystemsAdaptive Security Appliance Softwareoperating_system
Cisco SystemsFirepower Threat Defenseapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence3

Every observed campaign linking this CVE to a named adversary.

Associated malware9

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.