{"id":63833,"date":"2025-08-09T23:37:17","date_gmt":"2025-08-09T23:37:17","guid":{"rendered":""},"modified":"2025-09-06T12:48:45","modified_gmt":"2025-09-06T18:48:45","slug":"cve-2025-51726-weak-cryptographic-hash-and-lacking-high-entropy-aslr-in-cyberghostvpnsetup-exe","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-51726-weak-cryptographic-hash-and-lacking-high-entropy-aslr-in-cyberghostvpnsetup-exe\/","title":{"rendered":"<strong>CVE-2025-51726: Weak Cryptographic Hash and Lacking High Entropy ASLR in CyberGhostVPNSetup.exe<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The vulnerability CVE-2025-51726 presents a significant security risk to users of the CyberGhostVPNSetup.exe Windows installer. The software is exposed to potential supply-chain style attacks and privilege escalation through fake installers due to its use of the weak cryptographic hash algorithm SHA-1 and the absence of High Entropy Address Space Layout Randomization (ASLR). SHA-1 is susceptible to collision attacks, enabling malicious actors to forge SHA-1 certificates and craft fake <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-33075-a-critical-windows-installer-vulnerability-that-leads-to-privilege-elevation\/\"  data-wpil-monitor-id=\"72436\">installers that could be validated by Windows<\/a> signature verification mechanisms. This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-43192-critical-configuration-issue-in-macos-allowing-potential-system-compromise\/\"  data-wpil-monitor-id=\"71536\">issue is particularly critical on systems<\/a> without strict SmartScreen or trust policy enforcement.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-51726<br \/>\nSeverity: High (8.4 CVSS score)<br \/>\nAttack Vector: Local network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: Required<br \/>\nImpact: <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=\"75862\">Potential system<\/a> compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-289544530\" 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>CyberGhost VPN | All <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-55010-arbitrary-php-object-instantiation-in-kanboard-prior-to-version-1-2-47\/\"  data-wpil-monitor-id=\"78064\">versions prior<\/a> to patch<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The exploit works by taking advantage of the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-40920-weak-cryptographic-source-in-data-uuid-leads-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"79845\">weak SHA-1 cryptographic<\/a> hash used by the CyberGhostVPNSetup.exe Windows installer. A malicious actor crafts a fake installer with a forged SHA-1 certificate, which can then be accepted by Windows signature verification mechanisms, especially on systems without strict SmartScreen or trust policy enforcement in place.<br \/>\nMoreover, the installer lacks High Entropy ASLR, which allows the binary to consistently load into predictable memory ranges. This predictability increases the success rate of <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-21486-severe-memory-corruption-vulnerability-during-dynamic-process-creation\/\"  data-wpil-monitor-id=\"71535\">memory corruption<\/a> exploits. When these two vulnerabilities are combined, they significantly lower the bar for successful supply-chain style attacks or <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6754-privilege-escalation-vulnerability-in-seo-metrics-plugin-for-wordpress\/\"  data-wpil-monitor-id=\"72754\">privilege escalation<\/a> through fake installers.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-2236623729\" 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>This is a conceptual example of how the vulnerability might be exploited. The malicious actor could <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-31713-a-potential-privilege-escalation-vulnerability-due-to-command-injection\/\"  data-wpil-monitor-id=\"79487\">potentially employ a shell command<\/a> to generate a forged SHA-1 certificate and attach it to a malicious installer:<\/p>\n<pre><code class=\"\" data-line=\"\"># Generate SHA-1 hash for malicious installer\necho -n &quot;malicious_installer.exe&quot; | openssl dgst -sha1 -binary | openssl enc -base64\n# Craft malicious installer with forged certificate\ncopy \/b malicious_installer.exe+fake_certificate.exe new_installer.exe<\/code><\/pre>\n<p>Please note that this is a simplified and conceptual demonstration. In a real-world scenario, the process would likely involve more complex steps and tools, and the exploitation would require significant technical knowledge and resources.<\/p>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Users are strongly advised to apply the vendor patch as soon as it becomes available. Until then, they should consider implementing a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as a temporary mitigation measure to reduce the risk of successful exploitation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The vulnerability CVE-2025-51726 presents a significant security risk to users of the CyberGhostVPNSetup.exe Windows installer. The software is exposed to potential supply-chain style attacks and privilege escalation through fake installers due to its use of the weak cryptographic hash algorithm SHA-1 and the absence of High Entropy Address Space Layout Randomization (ASLR). SHA-1 is [&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":[82,99],"product":[100],"attack_vector":[76],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-63833","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft","vendor-openssl","product-openssl-libssl","attack_vector-privilege-escalation"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/63833","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=63833"}],"version-history":[{"count":7,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/63833\/revisions"}],"predecessor-version":[{"id":72285,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/63833\/revisions\/72285"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=63833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=63833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=63833"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=63833"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=63833"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=63833"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=63833"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=63833"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=63833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}