{"id":"CVE-2023-20269","published":"2023-09-06T18:15:08Z","modified":"2026-08-11T19:33:44Z","title":"Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability","vendor":"Cisco","product":"Adaptive Security Appliance and Firepower Threat Defense","tier":"core","eol":null,"description":{"text":"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.\r\n\r 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:\r\n\r \r Identify valid credentials that could then be used to establish an unauthorized remote access VPN session.\r Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier).\r \r Notes:\r\n\r \r 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.\r 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.\r \r Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability.","provenance":"source","from":"NVD"},"summary":null,"cvss":{"score":9.1,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","provenance":"source","from":"NVD"},"epss":{"score":0.26623,"percentile":0.98015,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2023-09-13","dueDate":"2023-10-04","ransomware":true,"requiredAction":"Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.","notes":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC;  https://nvd.nist.gov/vuln/detail/CVE-2023-20269","provenance":"source"},"vulncheckKev":{"dateAdded":"2023-08-29","exploitedFirstSeen":"2023-08-29","ransomware":true,"evidence":[{"url":"https://www.rapid7.com/blog/post/2023/08/29/under-siege-rapid7-observed-exploitation-of-cisco-asa-ssl-vpns/","date":"2023-08-29"},{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC","date":"2023-09-06"},{"url":"https://www.bleepingcomputer.com/news/security/cisco-warns-of-vpn-zero-day-exploited-by-ransomware-gangs/","date":"2023-09-08"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2023-09-13"},{"url":"https://www.intrinsec.com/akira_ransomware/","date":"2023-11-28"},{"url":"https://news.sophos.com/en-us/2023/12/21/akira-again-the-ransomware-that-keeps-on-taking/","date":"2023-12-21"},{"url":"https://www.coveware.com/blog/2024/1/25/new-ransomware-reporting-requirements-kick-in-as-victims-increasingly-avoid-paying","date":"2024-01-26"},{"url":"https://www.sentinelone.com/resources/watchtower-end-of-year-report-2023/","date":"2024-01-31"},{"url":"https://go.recordedfuture.com/hubfs/reports/cta-2024-0208.pdf","date":"2024-02-08"},{"url":"https://www.kroll.com/en/insights/publications/cyber/threat-intelligence-reports/q4-2023-threat-landscape-report-threat-actors-breach-outer-limits","date":"2024-02-21"}],"evidenceTotal":57,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"SafePay Ransomware Has Affected 600+ Organizations by Exploiting VPNs and Backup Servers","url":"https://otx.alienvault.com/pulse/6ad8700a0fe145230ba94c11","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"}],"provenance":"machine"},"cwes":[{"id":"CWE-863","name":"Incorrect Authorization"},{"id":"CWE-288","name":"Authentication Bypass Using an Alternate Path or Channel"}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC","tags":["Vendor Advisory"]},{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-20269","tags":["US Government Resource"]}],"techniques":[{"id":"T1133","name":"External Remote Services","tactics":["initial-access","persistence"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Improper Privilege Management","mappingType":"exploitation_technique","evidence":[],"comment":"This vulnerability is exploited by an unauthenticated, remote attacker by specifying a default connection profile/tunnel group, enabling a brute-force attack to identify valid credentials and establish a clienteles SSL VPN session using  those valid credentials.","confidence":"high"},{"id":"T1078","name":"Valid Accounts","tactics":["initial-access","persistence","privilege-escalation","stealth"],"provenance":"source","basis":"ctid-kev","bases":["ctid-kev"],"basisDetail":"CTID Mappings Explorer KEV 07/28/2025 (ATT&CK 16.1); capability: Improper Privilege Management","mappingType":"primary_impact","evidence":[],"comment":"This vulnerability is exploited by an unauthenticated, remote attacker by specifying a default connection profile/tunnel group, enabling a brute-force attack to identify valid credentials and establish a clienteles SSL VPN session using those valid credentials.","confidence":"high"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2023-24448","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-24448","exploited":true,"exploitedSince":"2023-09-13","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1133"],"provenance":"source"},{"stage":"primary","techniques":["T1078"],"provenance":"source"}],"timeline":[{"date":"2023-08-29","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://www.rapid7.com/blog/post/2023/08/29/under-siege-rapid7-observed-exploitation-of-cisco-asa-ssl-vpns/","provenance":"source"},{"date":"2023-09-06","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-20269","provenance":"source"},{"date":"2023-09-13","kind":"kev","label":"Added to CISA KEV (known ransomware use)","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2023-09-13","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-24448","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":7},"priority":{"score":74.0,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 1157 days ago"},{"name":"Known ransomware use","points":10.0,"detail":"CISA KEV and VulnCheck KEV: Known"},{"name":"EPSS percentile","points":19.6,"detail":"percentile 0.9801"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.37,"detail":"base score 9.1"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}