Описание
Microsoft Guidance on Scripting Engine Memory Corruption Vulnerability
Important Microsoft has completed the investigation into a public report of this vulnerability. We have issued CVE-2020-0674 - Scripting Engine Memory Corruption Vulnerability to address this vulnerability. For more information about this issue, including download links for an available security update, please review CVE-2020-0674.
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.
Меры по смягчению последствий
By default, Internet Explorer on Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016 and Windows Server 2019 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted web content on a server. This is a mitigating factor for websites that you have not added to the Internet Explorer Trusted sites zone.
Обходное решение
Impact of Workaround
Please note: Implementing these steps might result in reduced functionality for components or features that rely on jscript.dll. For example, depending on the environment, this could include client configurations that leverage proxy automatic configuration scripts (PAC scripts). These features and others may be impacted.
Microsoft recommends these mitigation steps only if there is indication that you are under elevated risk. If you implement the workaround, you will need to revert the mitigation steps before installing any future updates to continue to be protected.
By default, IE11, IE10, and IE9 uses Jscript9.dll which is not impacted by this vulnerability. This vulnerability only affects certain websites that utilize jscript as the scripting engine.
Restrict access to JScript.dll
For 32-bit systems, enter the following command at an administrative command prompt:
For 64-bit systems, enter the following command at an administrative command prompt:
How to undo the workaround
For 32-bit systems, enter the following command at an administrative command prompt:
For 64-bit systems, enter the following command at an administrative command prompt:
FAQ
Is there an update to address this vulnerability?
Yes, Microsoft has released the February security updates, which address this vulnerability. See CVE-2020-0674 for download links and more information.
Is Microsoft aware of attacks based on this vulnerability?
Yes, Microsoft is aware of limited targeted attacks.
Is there a CVE assigned to this vulnerability?
Yes, Microsoft has assigned CVE-2020-0674 to this vulnerability.
Возможность эксплуатации
DOS