CVE-2012-2522 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 through 9 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing a malformed virtual function table after this table s deletion, aka "Virtual Function Table Corruption Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 03/27/2021
This vulnerability resides in Microsoft Internet Explorer versions 6 through 9 and represents a critical memory corruption issue that enables remote code execution through improper handling of virtual function tables. The flaw occurs when Internet Explorer encounters malformed objects in memory, specifically targeting the virtual function table mechanism that governs object-oriented programming behavior in the browser's rendering engine. When a virtual function table is deleted from memory but subsequent code attempts to access it, the browser's memory management fails to properly validate these accesses, creating a condition where attackers can manipulate memory pointers to redirect execution flow.
The technical implementation of this vulnerability exploits the fundamental object-oriented programming concept of virtual function tables, which are data structures that enable dynamic dispatch of method calls in C++ applications. In Internet Explorer's case, when certain objects are destroyed or their memory is deallocated, the virtual function table pointers remain accessible in memory for a brief period. Attackers can craft malicious web content that triggers the creation of objects with specific memory layouts, causing the browser to access these corrupted virtual function tables after deletion. This memory access violation allows arbitrary code execution with the privileges of the currently logged-in user, making it particularly dangerous for web-based attacks.
The operational impact of CVE-2012-2522 extends far beyond simple browser exploitation, as it represents a classic use-after-free vulnerability that has been widely targeted by cybercriminals and nation-state actors. This vulnerability aligns with CWE-416, which describes the use of freed memory condition, and maps to ATT&CK technique T1203, which covers Exploitation for Client Execution. The vulnerability affects a broad range of Windows operating systems including Windows XP through Windows 7, making it particularly attractive to attackers seeking maximum impact. Security researchers have documented numerous real-world exploitation attempts where this vulnerability was used as an initial access vector in targeted attacks against enterprise networks, often combined with social engineering tactics to deliver malicious payloads through phishing emails or compromised websites.
Mitigation strategies for this vulnerability require immediate patch application from Microsoft, as the company released security updates specifically addressing this memory corruption issue in Internet Explorer 6 through 9. Organizations should implement comprehensive browser hardening measures including disabling unnecessary browser features, implementing sandboxing mechanisms, and deploying intrusion detection systems to monitor for exploitation attempts. Network-level protections such as web application firewalls and content filtering solutions can help detect and block malicious web content designed to exploit this vulnerability. Additionally, security teams should conduct regular vulnerability assessments targeting older Internet Explorer versions, as these browsers are no longer supported by Microsoft and remain susceptible to various memory corruption vulnerabilities. The vulnerability serves as a critical reminder of the importance of maintaining up-to-date software and implementing defense-in-depth strategies to protect against sophisticated exploitation techniques that target memory management flaws in web browsers.