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

Description

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.

Summary

CVE-2023-20269 is a critical (CVSS 9.1) flaw in the remote access VPN feature of Cisco ASA and FTD Software caused by improper AAA separation between the VPN feature and HTTPS management and site-to-site VPN features. An unauthenticated remote attacker could brute force valid username/password combinations, or an authenticated attacker could establish a clientless SSL VPN session as an unauthorized user (clientless sessions only on ASA Release 9.16 or earlier). Authentication is not bypassed, so valid credentials (and MFA, if configured) are still required. The flaw is listed in CISA's Known Exploited Vulnerabilities catalog with active exploitation, and EPSS gives a 26.6% chance of exploitation in 30 days. Apply Cisco's software updates, or use the vendor workarounds for group-lock and vpn-simultaneous-logins; discontinue use for unsupported devices.

CVE-2023-20269 ثغرة حرجة (CVSS 9.1) في ميزة VPN للوصول عن بُعد في برمجيات Cisco ASA وFTD، سببها فصل غير سليم لمكونات المصادقة والتفويض والمحاسبة (AAA) بين ميزة VPN وإدارتَي HTTPS وVPN من موقع إلى موقع. قد يتمكن مهاجم بعيد غير مصادَق من تنفيذ هجوم تخمين لكشف تركيبات صحيحة لأسماء المستخدمين وكلمات المرور، أو قد ينشئ مهاجم مصادَق جلسة SSL VPN بلا عميل بهوية مستخدم غير مصرّح له (الجلسات بلا عميل في Cisco ASA Software Release 9.16 أو أقدم فقط). لا تسمح الثغرة بتجاوز المصادقة، إذ تظل هناك حاجة إلى بيانات اعتماد صحيحة، بما في ذلك عامل ثانٍ صالح عند تفعيل MFA. الثغرة مدرجة في كتالوج CISA للثغرات المعروفة الاستغلال مع استغلال نشط، واحتمال الاستغلال خلال 30 يومًا وفق EPSS هو 26.6%. طبّق تحديثات برمجيات Cisco أو استخدم حلولًا بديلة من المورّد لإعدادَي group-lock وvpn-simultaneous-logins، وتوقف عن استخدام المنتج في الأجهزة غير المدعومة.

Affected products

References

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