CVE-2007-3902 in Internet Explorer
Summary
by MITRE
Use-after-free vulnerability in the CRecalcProperty function in mshtml.dll in Microsoft Internet Explorer 5.01 through 7 allows remote attackers to execute arbitrary code by calling the setExpression method and then modifying the outerHTML property of an HTML element, one variant of "Uninitialized Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 04/07/2017
The CVE-2007-3902 vulnerability represents a critical use-after-free flaw in Microsoft Internet Explorer's mshtml.dll component affecting versions 5.01 through 7. This vulnerability falls under the CWE-416 category of Use After Free, which occurs when a program continues to reference memory after it has been freed, creating opportunities for memory corruption and arbitrary code execution. The flaw specifically resides within the CRecalcProperty function where improper memory management allows attackers to manipulate object references beyond their intended lifecycle. The vulnerability manifests through a specific exploitation pattern involving the setExpression method followed by outerHTML property modification, creating an uninitialized memory corruption scenario that enables remote code execution.
The technical exploitation mechanism leverages the interaction between JavaScript and the HTML rendering engine where the setExpression method creates a dynamic property binding that, when combined with subsequent outerHTML modifications, triggers the use-after-free condition. This pattern creates a scenario where memory previously allocated to an object reference becomes available for reuse while the application still maintains references to it. The vulnerability's classification as an uninitialized memory corruption vulnerability demonstrates how improper memory deallocation combined with subsequent access patterns can lead to exploitable conditions that bypass modern security mitigations. The attack vector requires remote code execution through web-based exploitation, making it particularly dangerous in browser environments where users may inadvertently visit malicious websites.
Operationally, this vulnerability presents significant risk to organizations using affected Internet Explorer versions as it allows remote attackers to execute arbitrary code with the privileges of the logged-on user. The exploitation chain requires a user to visit a malicious website containing crafted JavaScript that triggers the specific memory corruption pattern. This vulnerability has been widely exploited in the wild, particularly in targeted attacks and drive-by download scenarios where attackers leverage the browser's rendering engine to deliver malware payloads. The impact extends beyond simple code execution to potentially enable full system compromise, privilege escalation, and data exfiltration capabilities. Security researchers have noted that the vulnerability's exploitation often bypasses standard security measures due to its deep integration with the browser's core rendering components.
Mitigation strategies for CVE-2007-3902 include immediate patching of affected Internet Explorer versions through Microsoft security updates, implementing browser security restrictions such as disabling JavaScript or limiting active scripting capabilities, and employing network-based security controls including web application firewalls and content filtering solutions. Organizations should also consider implementing security awareness training to reduce user exposure to malicious websites and phishing attacks that leverage this vulnerability. The vulnerability's age and widespread exploitation make it particularly important for legacy systems to be migrated away from unsupported Internet Explorer versions, as Microsoft has long since ended support for these products. Security monitoring should focus on detecting anomalous JavaScript behavior patterns and memory access violations that may indicate exploitation attempts, with particular attention to the specific setExpression and outerHTML property manipulation sequences that characterize this attack pattern.