Security Advisory - August 8, 2017
Zscaler protects against 1 new vulnerability for Internet Explorer
Zscaler, working with Microsoft through their MAPP program, has proactively deployed protection for the following 1 vulnerability included in the August 2017 Microsoft security bulletins. Zscaler will continue to monitor exploits associated with all vulnerabilities in the August release and deploy additional protections as necessary.
CVE-2017-8625 – Internet Explorer Security Feature Bypass Vulnerability
- Internet Explorer 11 on Windows 10 for 32-bit Systems
- Internet Explorer 11 on Windows 10 for x64-based Systems
- Internet Explorer 11 on Windows 10 Version 1511 for x64-based Systems
- Internet Explorer 11 on Windows 10 Version 1511 for 32-bit Systems
- Internet Explorer 11 on Windows Server 2016
- Internet Explorer 11 on Windows 10 Version 1607 for 32-bit Systems
- Internet Explorer 11 on Windows 10 Version 1607 for x64-based Systems
A security feature bypass vulnerability exists when Internet Explorer fails to validate User Mode Code Integrity (UMCI) policies. The vulnerability could allow an attacker to bypass Device Guard UCMI policies. To exploit the vulnerability, a user could either visit a malicious website or an attacker with access to the system could run a specially crafted application. An attacker could then leverage the vulnerability to run unsigned malicious code as though it were signed by a trusted source. The update addresses the vulnerability by correcting how Internet Explorer validates UMCI policies.