CVE-2012-4792

What is Microsoft Internet Explorer?

Microsoft Internet Explorer (IE) was the dominant web browser in enterprise environments throughout the 2000s and 2010s. IE uses a complex rendering engine that maintains C++ COM objects representing HTML elements and their relationships; the lifecycle of these objects — when they are created, referenced, and freed — was managed manually and was a persistent source of use-after-free vulnerabilities. Microsoft retired IE 11 in June 2022.

Overview

CVE-2012-4792 is a use-after-free vulnerability (CWE-416) in Microsoft Internet Explorer triggered by accessing a CDwnBindInfo object that has already been freed or was not properly allocated. Visiting a malicious web page with a vulnerable IE version triggers the vulnerability and allows arbitrary code execution in the context of the current user.

This vulnerability is notable for its exploitation in a strategic water-holing attack — attackers compromised the website of the Council on Foreign Relations (a prominent US foreign policy think tank) and silently served the exploit to visitors using Internet Explorer 8, targeting the US foreign policy community.

Microsoft released Security Advisory 2794220 with workarounds on December 29, 2012, and patched the vulnerability in the out-of-band emergency bulletin MS13-008 on January 14, 2013.

Affected Versions

Technical Details

The vulnerability is a use-after-free (CWE-416) in Internet Explorer's handling of CDwnBindInfo objects, which are used in IE's download binding infrastructure. When a web page causes IE to free a CDwnBindInfo object while a reference to it remains accessible (via JavaScript manipulation of the DOM or event handling), subsequent access to the freed memory triggers the use-after-free condition.

Use-after-free vulnerabilities in C++ COM objects follow a common exploitation pattern: the attacker uses JavaScript heap spray techniques to fill the freed memory region with attacker-controlled data before the freed pointer is dereferenced. When IE accesses the freed object, it treats the spray data as object fields, redirecting virtual function table (vtable) pointer lookups to attacker-controlled function pointers.

Attack delivery: The exploit was embedded in JavaScript on a compromised legitimate website — the Council on Foreign Relations site. Visitors using IE 8 on Windows XP were silently exploited; no user interaction beyond visiting the site was required.

Discovery

The compromise of the Council on Foreign Relations website was discovered by researchers in late December 2012. Analysis of the malicious JavaScript on the site revealed the previously unknown IE use-after-free zero-day. The sophistication of the water-holing attack and the high-value target selection are consistent with an Advanced Persistent Threat (APT) operation.

Exploitation Context

CVE-2012-4792 is a textbook example of a strategic water-holing attack — rather than directly targeting victims via spear-phishing, the attacker compromised a website frequented by the intended target community (US foreign policy professionals who read Council on Foreign Relations publications) and waited for victims to visit. This technique:

• Bypasses email security controls (no phishing email)
• Targets victims based on their interests/profession rather than requiring their email addresses
• Exploits the inherent trust users have in legitimate, high-reputation websites

The attack was linked to a likely Chinese state-sponsored APT group by researchers at Invincea who analyzed the malware payload delivered by the exploit.

CISA added this CVE to the KEV catalog in July 2024, a retroactive addition reflecting renewed acknowledgment of confirmed state-sponsored exploitation.

Remediation

Internet Explorer reached end-of-life on June 15, 2022. Organizations should:

1. Uninstall or disable Internet Explorer on all systems — Microsoft Edge replaced IE and is the supported browser
2. For historical remediation: MS13-008 (January 2013) patched this vulnerability
3. Audit Group Policy to ensure IE is disabled and users cannot invoke it (including via legacy IE mode in Edge if not needed)
4. Review any applications that depend on Internet Explorer for automation or rendering — migrate these to Edge WebView2 or modern alternatives