Microsoft Windows VBScript InStr/InStrRev Functions Use-After-Free Information Disclosure Vulnerability

2015-12-08T00:00:00
ID ZDI-15-594
Type zdi
Reporter Simon Zuckerbraun - HP Zero Day Initiative
Modified 2015-11-09T00:00:00

Description

This vulnerability allows remote attackers to disclose the contents of memory on applications using the VBScript scripting language on vulnerable installations of Microsoft Windows. Microsoft Internet Explorer is an affected application. 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 implementation of the VBScript InStr and InStrRev functions. By supplying specially crafted parameters, an attacker can disclose the contents of memory. An attacker can use this information in conjunction with other vulnerabilities to execute code in the context of the process.