Microsoft Internet Explorer Cumulative Security Update

Last Update Date: 16 Dec 2014 Release Date: 10 Dec 2014 3880 Views

RISK: High Risk

TYPE: Clients - Browsers

Multiple Memory Corruption Vulnerabilities in Internet Explorer
Remote code execution vulnerabilities exist when Internet Explorer improperly accesses objects in memory. These vulnerabilities could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. The update addresses the vulnerabilities by modifying the way that Internet Explorer handles objects in memory.

An attacker could host a specially crafted website that is designed to exploit these vulnerabilities through Internet Explorer, and then convince a user to view the website. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements by adding specially crafted content that could exploit these vulnerabilities. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to click a link in an email message or in an Instant Messenger message that takes users to the attacker's website, or by getting them to open an attachment sent through email.

Multiple XSS Filter Bypass Vulnerabilities in Internet Explorer
XSS filter bypass vulnerabilities exist in the way that Internet Explorer disables an HTML attribute in otherwise appropriately filtered HTTP response data. The vulnerabilities could allow initially disabled scripts to run in the wrong security context, leading to information disclosure.

An attacker could post on a website specially crafted content that is designed to exploit this vulnerability. The attacker would then have to convince the user to view the content on the affected website. If the user then browses to the website, the XSS filter disables HTML attributes in the specially crafted content, creating a condition that could allow malicious script to run in the wrong security context, leading to information disclosure.

Internet Explorer ASLR Bypass Vulnerability
A security feature bypass vulnerability exists when Internet Explorer does not use the Address Space Layout Randomization (ASLR) security feature, allowing an attacker to more reliably predict the memory offsets of specific instructions in a given call stack. An attacker who successfully exploited this vulnerability could bypass the Address Space Layout Randomization (ASLR) security feature, which helps protect users from a broad class of vulnerabilities. The security feature bypass by itself does not allow arbitrary code execution. However, an attacker could use this ASLR bypass vulnerability in conjunction with another vulnerability, such as a remote code execution vulnerability, that could take advantage of the ASLR bypass to run arbitrary code. For example, a remote code execution vulnerability that is blocked by ASLR, could be exploited after a successful ASLR bypass.

VBScript Memory Corruption Vulnerability
A remote code execution vulnerability exists in the way that the VBScript engine, when rendered in Internet Explorer, handles objects in memory. The vulnerability may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.

An attacker could host a specially crafted website that is designed to exploit this vulnerability through Internet Explorer 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 IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements by adding specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically by getting them to click a link in an email message or in an Instant Messenger message that takes users to the attacker's website, or by opening an attachment sent through email.