{"id":64273,"date":"2025-08-23T22:10:46","date_gmt":"2025-08-23T22:10:46","guid":{"rendered":""},"modified":"2025-10-03T12:33:06","modified_gmt":"2025-10-03T18:33:06","slug":"cve-2025-20217-denial-of-service-vulnerability-in-snort-3-detection-engine-of-cisco-secure-firewall-threat-defense-software","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-20217-denial-of-service-vulnerability-in-snort-3-detection-engine-of-cisco-secure-firewall-threat-defense-software\/","title":{"rendered":"<strong>CVE-2025-20217: Denial of Service Vulnerability in Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense Software<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The world of cybersecurity is a constant battleground, and a new vulnerability has emerged that puts numerous systems at risk. The vulnerability in question, denoted by the Common Vulnerabilities and Exposures (CVE) system as CVE-2025-20217, affects the packet inspection functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software. This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-43275-critical-race-condition-vulnerability-in-macos\/\"  data-wpil-monitor-id=\"71650\">critical vulnerability<\/a> could be exploited by an attacker to cause a Denial of Service (DoS) condition on targeted systems, potentially causing significant disruptions and compromises to system operations.<br \/>\nAs a <a href=\"https:\/\/www.ameeba.com\/blog\/introducing-the-ameeba-cybersecurity-group-chat\/\"  data-wpil-monitor-id=\"88505\">cybersecurity<\/a> expert, it is crucial to understand the nature of this vulnerability, how it could be exploited, and most importantly, how to mitigate its risks. This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30327-integer-overflow-vulnerability-in-incopy-leading-to-potential-arbitrary-code-execution\/\"  data-wpil-monitor-id=\"73703\">vulnerability is particularly concerning due to its potential<\/a> for widespread impact and its high CVSS Severity Score of 8.6, indicating a high level of severity.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-20217<br \/>\nSeverity: High (8.6 CVSS Severity Score)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: Denial of Service condition <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49691-heap-based-buffer-overflow-in-windows-media-leading-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"72203\">leading to potential system<\/a> compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-497844999\" class=\"ameeb-content-2 ameeb-entity-placement\"><div style=\"border-left: 4px solid #555; padding-left: 20px; margin: 48px 0; font-family: Roboto, sans-serif; color: #ffffff; line-height: 1.6; max-width: 720px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 22px; font-weight: 600; display: flex; align-items: center; letter-spacing: -0.02em;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 10px;\">\r\n      <img decoding=\"async\" src=\"https:\/\/www.ameeba.com\/blog\/wp-content\/uploads\/2025\/10\/Best-App-icon-Ameeba.png\" alt=\"Ameeba Chat Icon\" style=\"width: 42px; height: 42px;\" \/>\r\n    <\/a>\r\n    Share secrets securely\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 14px; color: #d1d5db;\">\r\n    Ameeba is private infrastructure for communication and sensitive work built on encrypted identity instead of exposed corporate identity systems.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 18px; color: #a1a1aa;\">\r\n    Passwords, credentials, confidential files, screenshots, internal discussions, sensitive AI context, and private coordination should not become exposed across ordinary communication platforms.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 24px; color: #e4e4e7;\">\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Encrypted identity<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Private Spaces for organizations and teams<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 End-to-end encrypted chat, calls, files, and notes<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Sensitive AI work and protected collaboration<\/li>\r\n    <li>\u2022 Built for information that cannot leak<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px; color: #ffffff;\">\r\n    Our mission is to secure human work alongside AI.\r\n  <\/p>\r\n\r\n  <div style=\"display: flex; flex-wrap: wrap; gap: 12px;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\/download\" style=\"background-color: #ffffff; color: #000000; padding: 10px 20px; text-decoration: none; border-radius: 8px; font-weight: 500;\">\r\n      Download Ameeba\r\n    <\/a>\r\n\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 8px; font-weight: 500;\">\r\n      Learn More\r\n    <\/a>\r\n  <\/div>\r\n<\/div><\/div>\n<p>Product | Affected Versions<\/p>\n<p><a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-20133-remote-access-ssl-vpn-vulnerability-in-cisco-secure-firewall-asa-software-and-secure-ftd-software\/\"  data-wpil-monitor-id=\"76822\">Cisco Secure Firewall<\/a> Threat Defense (FTD) Software | All versions running Snort 3 Detection Engine<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8028-critical-vulnerability-in-firefox-and-thunderbird-due-to-incorrect-computation-of-branch-address\/\"  data-wpil-monitor-id=\"73820\">vulnerability arises from incorrect<\/a> processing of traffic by an affected device. An attacker can exploit this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30133-device-pairing-bypass-vulnerability-in-iroad-dashcam-fx2-devices\/\"  data-wpil-monitor-id=\"75646\">vulnerability by sending carefully crafted traffic through the vulnerable device<\/a>. This malicious traffic causes the affected device to enter an infinite loop while inspecting the traffic, resulting in a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-20253-critical-vulnerability-in-ikev2-feature-of-cisco-software-could-lead-to-denial-of-service-dos-attack\/\"  data-wpil-monitor-id=\"76167\">Denial of Service<\/a> (DoS) condition. The affected system&#8217;s watchdog will restart the Snort process automatically, but the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27046-critical-memory-corruption-vulnerability-threatening-system-integrity\/\"  data-wpil-monitor-id=\"75067\">system remains vulnerable<\/a> to subsequent attacks.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-2218326191\" class=\"ameeb-content ameeb-entity-placement\"><div class=\"poptin-embedded\" data-id=\"f6b387694f681\"><\/div>\r\n\r\n\r\n\r\n\r\n\r\n<\/div>\n<p>The following conceptual example illustrates how an attacker might craft <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8714-critical-postgresql-vulnerability-allowing-malicious-code-injection-by-superusers\/\"  data-wpil-monitor-id=\"80763\">malicious traffic to exploit this vulnerability<\/a>. However, for ethical and security reasons, specific details are omitted.<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/json\n{ &quot;malicious_payload&quot;: &quot;crafted_data_causing_infinite_loop&quot; }<\/code><\/pre>\n<p>In this example, the attacker sends a POST request to a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-40741-stack-based-overflow-vulnerability-in-solid-edge-se2025-leading-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"75764\">vulnerable endpoint on the target system<\/a>. The payload (&#8220;crafted_data_causing_infinite_loop&#8221;) is designed to induce an infinite loop in the Snort 3 Detection Engine, causing a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-20136-denial-of-service-vulnerability-in-cisco-secure-firewall-asa-and-ftd-software\/\"  data-wpil-monitor-id=\"76914\">Denial of Service<\/a> condition.<\/p>\n<p><strong>Recommendations for Mitigation<\/strong><\/p>\n<p>The recommended mitigation for this vulnerability is to apply the vendor&#8217;s patch as soon as it becomes available. In the meantime, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation by detecting and blocking malicious traffic. Regularly updating your security <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2023-41530-critical-sql-injection-vulnerability-in-hospital-management-system-v4\/\"  data-wpil-monitor-id=\"75924\">systems and maintaining awareness of new vulnerabilities<\/a> are key steps in protecting your systems from cybersecurity threats.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The world of cybersecurity is a constant battleground, and a new vulnerability has emerged that puts numerous systems at risk. The vulnerability in question, denoted by the Common Vulnerabilities and Exposures (CVE) system as CVE-2025-20217, affects the packet inspection functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[96],"product":[],"attack_vector":[87],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-64273","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-cisco","attack_vector-dos"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64273","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/comments?post=64273"}],"version-history":[{"count":13,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64273\/revisions"}],"predecessor-version":[{"id":81311,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64273\/revisions\/81311"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=64273"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=64273"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=64273"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=64273"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=64273"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=64273"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=64273"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=64273"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=64273"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}