{"id":34035,"date":"2025-05-01T08:17:20","date_gmt":"2025-05-01T08:17:20","guid":{"rendered":""},"modified":"2025-05-19T06:52:08","modified_gmt":"2025-05-19T06:52:08","slug":"cve-2025-43715-privilege-escalation-vulnerability-in-nullsoft-scriptable-install-system-nsis","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-43715-privilege-escalation-vulnerability-in-nullsoft-scriptable-install-system-nsis\/","title":{"rendered":"CVE-2025-43715: Privilege Escalation Vulnerability in Nullsoft Scriptable Install System (NSIS)<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

CVE-2025-43715 is a significant security vulnerability that affects the Nullsoft Scriptable Install System (NSIS) on Windows platforms. This vulnerability allows local users to escalate their privileges to SYSTEM during an installation process. It pertains to how NSIS handles temporary plugins directory creation during installations, making it susceptible to race condition<\/a> exploits. The vulnerability is of particular concern because it could potentially enable system compromise or data<\/a> leakage, posing a serious risk to users and their sensitive information.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-43715
\nSeverity: High (8.1 CVSS v3.0 Score)
\nAttack Vector: Local
\nPrivileges Required: Low
\nUser Interaction: Required
\nImpact: System compromise<\/a> or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

Nullsoft Scriptable Install System | Before 3.11<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit of CVE-2025-43715 revolves around the temporary plugins directory that NSIS creates under %WINDIR%temp during an installation<\/a> process. By winning a race condition, unprivileged users can place a crafted executable<\/a> file in this directory. Since NSIS’s EW_CREATEDIR does not always set the CreateRestrictedDirectory error flag, this allows the system to execute the crafted file with elevated SYSTEM privileges, leading to a potential system<\/a> compromise or data leakage.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Even though the actual exploit process involves wining a race condition<\/a> and is complex to show in a simple code example, the conceptual pseudo-code below provides a simplified idea of how this vulnerability might be exploited:<\/p>\n

# pseudo-code\nimport os\nimport shutil\n# Locate the temporary plugins directory\ntemp_dir = os.environ['WINDIR'] + '\/temp'\n# Crafted executable content\ncrafted_exe = '...'\n# Wait for the right moment (race condition)\nwhile not os.path.exists(temp_dir):\npass\n# Write the crafted executable to the temporary plugins directory\nwith open(os.path.join(temp_dir, 'crafted.exe'), 'w') as f:\nf.write(crafted_exe)\n# The crafted executable will be executed with SYSTEM privileges during NSIS installation<\/code><\/pre>\n
Mitigation Guidance<\/strong><\/p>\n
Users are recommended to apply the vendor-provided patch as soon as possible. If applying the patch immediately is not an option, using Web Application Firewalls (WAF) or Intrusion Detection Systems (IDS) can serve as a temporary mitigation measure. However, these do not completely remediate the vulnerability and are merely stopgap solutions<\/a>. The only comprehensive solution is to update NSIS to a version that has addressed this vulnerability<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview CVE-2025-43715 is a significant security vulnerability that affects the Nullsoft Scriptable Install System (NSIS) on Windows platforms. This vulnerability allows local users to escalate their privileges to SYSTEM during an installation process. It pertains to how NSIS handles temporary plugins directory creation during installations, making it susceptible to race condition exploits. The vulnerability is […]<\/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,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[82],"product":[],"attack_vector":[76],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-34035","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft","attack_vector-privilege-escalation"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t