CVE-2019-0988: Microsoft Windows jscript9 RegExp.input Type Confusion Remote Code Execution Vulnerability

A remote code execution vulnerability exists in the way the scripting engine handles objects in memory in Microsoft browsers. 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 designed to exploit the vulnerability through a Microsoft browser and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the browser rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability. The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.

— Microsoft

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft Windows. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the way the JIT compiler handles the RegExp.input property in jscript9.dll. By performing actions in JavaScript, an attacker can trigger a type confusion condition. An attacker can leverage this vulnerability to execute code in the context of the current process.

— ZDI