Microsoft released a hefty load of security bulletins today, which included a patch for a JScript and VBScript scripting engine vulnerability being publicly exploited.
The flaw is addressed in its own bulletin, MS16-053, but users need to pay attention to, and apply MS16-051 as well since the attack vector is through Internet Explorer.
MS16-051 addresses the issue in IE 9, 10 and 11; MS16-053 patches the flaw in IE 7 and earlier supported versions of the browser.
The flaw, CVE-2016-0189, is one of two memory corruption vulnerabilities in the scripting engines. Both enable arbitrary code execution if a victim, via IE, lands on an attacker’s site hosting the exploit; CVE-2016-0187 is the other flaw in the scripting engines patched today. Microsoft said the flaws exist because of how JScript and VBScript handle objects in memory in IE. VBScript 5.7 is vulnerable on Windows Vista, Windows Server 2008 and the Server Core installation option, while JScript 5.8 and VBScript 5.8 are vulnerable on Windows Server 2008 R2 for x64 Systems Service Pack 1 are vulnerable on the Server Core installation only.