CVE-2012-0170 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 and 7 does not properly handle objects in memory, which allows remote attackers to execute arbitrary code by accessing a deleted object, aka "OnReadyStateChange Remote Code Execution Vulnerability."
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Analysis
by VulDB Data Team • 03/22/2021
The vulnerability identified as CVE-2012-0170 represents a critical memory corruption flaw in Microsoft Internet Explorer versions 6 and 7 that enables remote code execution through improper object handling in memory management. This vulnerability specifically affects the browser's handling of objects during the OnReadyStateChange event, which occurs when an HTML element's ready state changes during document loading or script execution. The flaw stems from the browser's failure to properly validate object references after memory deallocation, creating a scenario where attackers can manipulate memory contents to execute malicious code with the privileges of the affected user.
The technical exploitation of this vulnerability occurs when Internet Explorer attempts to access an object that has already been freed from memory but not properly invalidated in the browser's memory management system. During normal operation, when HTML elements or script objects are removed from the document object model, they should be properly dereferenced and their memory should be marked as invalid. However, in affected versions of IE6 and IE7, the browser's memory management logic fails to prevent subsequent access to these freed objects, allowing attackers to craft malicious web pages that trigger the execution of arbitrary code. This memory corruption vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions where programs access memory beyond allocated boundaries.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete system compromise capabilities when users visit malicious websites or open compromised email attachments containing crafted HTML content. The vulnerability's exploitation requires minimal user interaction, typically only the act of visiting a malicious website, making it particularly dangerous in enterprise environments where users may inadvertently encounter compromised web content. Security researchers have documented this vulnerability being actively exploited in the wild, with threat actors leveraging it as part of initial access vectors for more sophisticated attack chains. The attack pattern aligns with ATT&CK technique T1203, which describes the use of web-based exploitation to gain initial access to target systems.
Mitigation strategies for CVE-2012-0170 primarily involve immediate patching of affected systems with Microsoft security updates, as well as implementing browser hardening measures to reduce the attack surface. Organizations should consider deploying web application firewalls and implementing content security policies to prevent execution of malicious scripts from untrusted sources. Additionally, security teams should enforce strict browser configuration policies that disable unnecessary ActiveX controls and scripting capabilities, particularly in high-risk environments. The vulnerability demonstrates the critical importance of proper memory management in web browsers and highlights the need for continuous security assessments of browser components. Organizations should also implement network monitoring to detect potential exploitation attempts and maintain comprehensive incident response procedures to address potential compromise. The vulnerability serves as a reminder of the importance of keeping browser software up to date and the risks associated with using deprecated browser versions that no longer receive security updates.