Microsoft Internet Explorer Remote Code Execution Vulnerability (CVE-2019-1367) Threat Alert

1 Vulnerability Description

On September 23, local time, Microsoft released cumulative security updates for the Internet Explorer (IE), fixing a remote code execution vulnerability (CVE-2019-1367) in IE. This vulnerability exists in the way the IE’s script engine handles objects in memory. By tricking a user into accessing a crafted website through IE, an attacker could exploit this vulnerability to execute arbitrary code to finally gain control access to the system.

Currently, Microsoft has released security patches. Users are advised to download the patches from the following links and apply them as soon as possible:

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2019-1367

https://support.microsoft.com/zh-cn/help/4522007/cumulative-security-update-for-internet-explorer

2 Scope of Impact

Affected Versions

• Internet Explorer 9
• Internet Explorer 10
• Internet Explorer11

3 Mitigation

3.1 Official Patches

Microsoft has not released updates through Windows Update or Windows Server Update Services (WSUS), but has released an independent security update to fix this vulnerability. Affected users are advised to download these updates as soon as possible.

3.2 Workarounds

If users cannot install patches for the time being, they can adopt the following temporary measures to protect against this vulnerability:

For a 32-bit Windows system, open a command prompt window with administrative privileges and run the following commands:

takeown /f %windir%\system32\jscript.dll

cacls%windir%\system32\jscript.dll /E /P everyone:N

For a 64-bit Windows system, open a command prompt window with administrative privileges and run the following commands:

takeown /f%windir%\syswow64\jscript.dll

cacls%windir%\syswow64\jscript.dll /E /P everyone:N/font>

takeown /f%windir%\system32\jscript.dll/font>

Note: Due to the preceding workarounds, some system functions may be restricted. If a system exception occurs or security patches are already installed, the user should undo the applied workaround in either of the following ways:

For a 32-bit Windows system, open a command prompt window with administrative privileges and run the following commands:

cacls %windir%\system32\jscript.dll /E /R everyone/font>

For a 64-bit Windows system, open a command prompt window with administrative privileges and run the following commands:

cacls %windir%\system32\jscript.dll /E /R everyone/font>

cacls %windir%\syswow64\jscript.dll /E /R everyone/font>

Appendix

• Statement

This advisory is only used to describe a potential risk. NSFOCUS does not provide any commitment or promise on this advisory. NSFOCUS and the author will not bear any liability for any direct and/or indirect consequences and losses caused by transmitting and/or using this advisory. NSFOCUS reserves all the rights to modify and interpret this advisory. Please include this statement paragraph when reproducing or transferring this advisory. Do not modify this advisory, add/delete any information to/from it, or use this advisory for commercial purposes without permission from NSFOCUS.

• About NSFOCUS

NSFOCUS, Inc., a global network and cyber security leader, protects enterprises and carriers from advanced cyber attacks. The company’s Intelligent Hybrid Security strategy utilizes both cloud and on-premises security platforms, built on a foundation of real-time global threat intelligence, to provide multi-layered, unified and dynamic protection against advanced cyber attacks.

NSFOCUS works with Fortune Global 500 companies, including four of the world’s five largest financial institutions, organizations in insurance, retail, healthcare, critical infrastructure industries as well as government agencies. NSFOCUS has technology and channel partners in more than 60 countries, is a member of both the Microsoft Active Protections Program (MAPP), and the Cloud Security Alliance (CSA).

A wholly owned subsidiary of NSFOCUS Information Technology Co. Ltd., the company has operations in the Americas, Europe, the Middle East and Asia Pacific.