CVE-2012-1878 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 deleted object, aka "OnBeforeDeactivate Event Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 03/25/2021
The vulnerability identified as CVE-2012-1878 represents a critical memory management flaw in Microsoft Internet Explorer versions 6 through 9 that enables remote code execution through improper object handling in memory. This vulnerability specifically affects the browser's treatment of objects during the deactivation process, creating a condition where attackers can exploit a deleted object reference to execute malicious code on vulnerable systems. The flaw stems from how Internet Explorer manages object lifecycles and memory cleanup operations, particularly when processing the OnBeforeDeactivate event which occurs during the browser's object destruction sequence. This vulnerability is classified under CWE-476 as a NULL Pointer Dereference, though it manifests through more complex memory corruption mechanisms that enable arbitrary code execution rather than simple pointer dereference.
The technical exploitation of this vulnerability occurs when Internet Explorer encounters a scenario where an object is accessed after it has been deleted from memory but before the memory has been properly deallocated. During the OnBeforeDeactivate event processing, the browser maintains references to objects that may have already been marked for deletion, creating a window where malicious code can manipulate the object state or inject execution payloads into the memory space. Attackers typically craft malicious web pages that trigger the vulnerable code path by creating specific object interactions that cause the browser to access freed memory locations, leading to memory corruption that can be leveraged for code execution. This type of vulnerability falls under the ATT&CK technique T1203 - Exploitation for Client Execution, specifically targeting browser-based attack vectors.
The operational impact of CVE-2012-1878 is severe given the widespread adoption of Internet Explorer 6 through 9 across enterprise and consumer environments during the affected period. Organizations running these older browser versions faced significant risk exposure as the vulnerability could be exploited through standard web browsing activities without user interaction, making it particularly dangerous for targeted attacks. The vulnerability's exploitation does not require user interaction beyond visiting a malicious website, making it a prime candidate for drive-by download attacks and automated exploitation campaigns. Security researchers have noted that the memory corruption patterns associated with this vulnerability often result in reliable code execution, making it a preferred target for malware authors seeking to establish persistent access to compromised systems. The vulnerability's impact extends beyond simple remote code execution as it can be combined with other techniques to escalate privileges or bypass security controls.
Mitigation strategies for CVE-2012-1878 primarily focus on browser version upgrades and implementation of security controls that prevent exploitation of the memory handling flaw. Microsoft released security updates that addressed the object lifecycle management issues in Internet Explorer, though organizations with legacy systems requiring continued use of older IE versions needed to implement additional protective measures. Recommended mitigations include disabling Active Scripting, implementing proper browser security zones, and deploying web application firewalls that can detect and block malicious content targeting this vulnerability. Network administrators should also consider implementing browser isolation techniques and ensuring that users cannot access potentially malicious websites through restricted browsing policies. The vulnerability demonstrates the importance of proper memory management in browser security and has influenced subsequent browser development practices to include more robust object lifecycle handling and memory protection mechanisms. Organizations should also maintain updated vulnerability management processes to identify and remediate similar memory corruption issues that may exist in other browser components or web applications.