Zscaler, working with Microsoft through their MAPP program, has proactively deployed protection for the following 2 vulnerability included in the January 2020 Microsoft security bulletins. Zscaler will continue to monitor exploits associated with all vulnerabilities in the January release and deploy additional protections as necessary.

CVE-2020-0601 – Windows CryptoAPI Spoofing Vulnerability

Severity: Critical

Affected Software

Windows 10 for 32-bit Systems
Windows 10 for x64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows 10 Version 1709 for 32-bit Systems
Windows 10 Version 1709 for ARM64-based Systems
Windows 10 Version 1709 for x64-based Systems
Windows 10 Version 1803 for 32-bit Systems
Windows 10 Version 1803 for ARM64-based Systems
Windows 10 Version 1803 for x64-based Systems
Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for ARM64-based Systems
Windows 10 Version 1809 for x64-based Systems
Windows 10 Version 1903 for 32-bit Systems
Windows 10 Version 1903 for ARM64-based Systems
Windows 10 Version 1903 for x64-based Systems
Windows 10 Version 1909 for 32-bit Systems
Windows 10 Version 1909 for ARM64-based Systems
Windows 10 Version 1909 for x64-based Systems
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server, version 1803 (Server Core Installation)
Windows Server, version 1903 (Server Core installation)
Windows Server, version 1909 (Server Core installation)

A spoofing vulnerability exists in the way Windows CryptoAPI (Crypt32.dll) validates Elliptic Curve Cryptography (ECC) certificates. An attacker could exploit the vulnerability by using a spoofed code-signing certificate to sign a malicious executable, making it appear the file was from a trusted, legitimate source. The user would have no way of knowing the file was malicious, because the digital signature would appear to be from a trusted provider. A successful exploit could also allow the attacker to conduct man-in-the-middle attacks and decrypt confidential information on user connections to the affected software. The security update addresses the vulnerability by ensuring that Windows CryptoAPI completely validates ECC certificates

CVE-2020-0634 – Windows Common Log File System Driver Elevation of Privilege Vulnerability

Severity: Important

Affected Software

Windows 10 for 32-bit Systems
Windows 10 for x64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows 10 Version 1709 for 32-bit Systems
Windows 10 Version 1709 for ARM64-based Systems
Windows 10 Version 1709 for x64-based Systems
Windows 10 Version 1803 for 32-bit Systems
Windows 10 Version 1803 for ARM64-based Systems
Windows 10 Version 1803 for x64-based Systems
Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for ARM64-based Systems
Windows 10 Version 1809 for x64-based Systems
Windows 10 Version 1903 for 32-bit Systems
Windows 10 Version 1903 for ARM64-based Systems
Windows 10 Version 1903 for x64-based Systems
Windows 10 Version 1909 for 32-bit Systems
Windows 10 Version 1909 for ARM64-based Systems
Windows 10 Version 1909 for x64-based Systems
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows 8.1 for 32-bit systems
Windows 8.1 for x64-based systems
Windows RT 8.1
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
Windows Server 2008 for Itanium-Based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Windows Server 2012
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Server Core installation)
Windows Server 2016
Windows Server 2016 (Server Core installation)
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server, version 1803 (Server Core Installation)
Windows Server, version 1903 (Server Core installation)
Windows Server, version 1909 (Server Core installation)

An elevation of privilege vulnerability exists when the Windows Common Log File System (CLFS) driver improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run processes in an elevated context. To exploit the vulnerability, an attacker would first have to log on to the system, and then run a specially crafted application to take control over the affected system. The security update addresses the vulnerability by correcting how CLFS handles objects in memory.

CVE-2020-0674 – Scripting Engine Memory Corruption Vulnerability [Updated – January 20, 2020]

Severity: Critical

Affected Software

Internet Explorer 10 for Windows Server 201
Internet Explorer 11 for Windows 10 Version 1803 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1803 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1803 for ARM64-based Systems
Internet Explorer 11 for Windows 10 Version 1809 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1809 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1809 for ARM64-based Systems
Internet Explorer 11 for Windows Server 2019
Internet Explorer 11 for Windows 10 Version 1909 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1909 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1909 for ARM64-based Systems
Internet Explorer 11 for Windows 10 Version 1709 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1709 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1709 for ARM64-based Systems
Internet Explorer 11 for Windows 10 Version 1903 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1903 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1903 for ARM64-based Systems
Internet Explorer 11 for Windows 10 for 32-bit Systems
Internet Explorer 11 for Windows 10 for x64-based Systems
Internet Explorer 11 for Windows 10 Version 1607 for 32-bit Systems
Internet Explorer 11 for Windows 10 Version 1607 for x64-based Systems
Internet Explorer 11 for Windows Server 2016
Internet Explorer 11 for Windows 7 for 32-bit Systems Service Pack 1
Internet Explorer 11 for Windows 7 for x64-based Systems Service Pack 1
Internet Explorer 11 for Windows 8.1 for 32-bit systems
Internet Explorer 11 for Windows 8.1 for x64-based systems
Internet Explorer 11 for Windows RT 8.1
Internet Explorer 11 for Windows Server 2008 R2 for x64-based Systems Service Pack 1
Internet Explorer 11 for Windows Server 2012
Internet Explorer 11 for Windows Server 2012 R2
Internet Explorer 9 for Windows Server 2008 for 32-bit Systems Service Pack 2
Internet Explorer 9 for Windows Server 2008 for x64-based Systems Service Pack 2

A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website, for example, by sending an email.