{"id":"CVE-2024-20481","published":"2024-10-23T18:15:11Z","modified":"2026-08-11T19:40:47Z","title":"Cisco ASA and FTD Denial-of-Service Vulnerability","vendor":"Cisco","product":"Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)","tier":"core","eol":null,"description":{"text":"A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service.\r\n\r This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authentication requests to an affected device. A successful exploit could allow the attacker to exhaust resources, resulting in a DoS of the RAVPN service on the affected device. Depending on the impact of the attack, a reload of the device may be required to restore the RAVPN service. Services that are not related to VPN are not affected.\r\n\r Cisco Talos discussed these attacks in the blog post Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials.","provenance":"source","from":"NVD"},"summary":{"text":"A flaw in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software causes resource exhaustion that can disrupt that service. An unauthenticated attacker on the network can trigger a denial of service of RAVPN by sending a large number of VPN authentication requests to an affected device, with no user interaction required, and recovery may require a device reload; services not related to VPN are not affected.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:14:09Z"},"cvss":{"score":5.8,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L","provenance":"source","from":"NVD"},"epss":{"score":0.15874,"percentile":0.96878,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2024-10-24","dueDate":"2024-11-14","ransomware":false,"requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","notes":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-bf-dos-vDZhLqrW ; https://nvd.nist.gov/vuln/detail/CVE-2024-20481","provenance":"source"},"vulncheckKev":{"dateAdded":"2024-10-23","exploitedFirstSeen":"2024-10-23","ransomware":false,"evidence":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-bf-dos-vDZhLqrW","date":"2024-10-23"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2024-10-24"},{"url":"https://eclypsium.com/blog/cisco-asa-scanning-surge-cyberattack/","date":"2025-09-16"}],"evidenceTotal":3,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"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":"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-772","name":"Missing Release of Resource after Effective Lifetime"}],"references":[{"url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-bf-dos-vDZhLqrW","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20481","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Unauthenticated remote attack against public-facing VPN service","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"could allow an unauthenticated, remote attacker to cause a denial of service","start":159,"end":235}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1499.004","name":"Application or System Exploitation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Resource exhaustion via flooding causes application-layer DoS","mappingType":"primary_impact","evidence":[{"from":"description","quote":"sending a large number of VPN authentication requests to an affected device","start":365,"end":440}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2024-18196","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2024-18196","exploited":true,"exploitedSince":"2024-10-24","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1499.004"],"provenance":"ai"}],"timeline":[{"date":"2024-10-23","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-20481","provenance":"source"},{"date":"2024-10-23","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-bf-dos-vDZhLqrW","provenance":"source"},{"date":"2024-10-24","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2024-10-24","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2024-18196","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":1},"priority":{"score":61.4,"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 737 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.38,"detail":"percentile 0.9688"},{"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":4.06,"detail":"base score 5.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"familyId":"fam-class-cisco-asa-cwe-772"}}