CVE-2006-4495 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer allows remote attackers to cause a denial of service (memory corruption) and possibly execute arbitrary code by instantiating certain Windows 2000 ActiveX COM Objects including (1) ciodm.dll, (2) myinfo.dll, (3) msdxm.ocx, and (4) creator.dll.
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Analysis
by VulDB Data Team • 04/30/2019
This vulnerability resides within Microsoft Internet Explorer's handling of ActiveX COM objects on Windows 2000 systems, representing a critical memory corruption flaw that can be exploited remotely. The issue specifically affects the browser's object instantiation mechanism when processing certain legacy ActiveX controls including ciodm.dll, myinfo.dll, msdxm.ocx, and creator.dll. These components are vulnerable due to improper input validation and memory management during object creation and method invocation processes. The flaw allows attackers to manipulate memory structures through crafted web content that triggers the instantiation of these specific COM objects, leading to unpredictable behavior in the browser's memory space.
The technical exploitation of this vulnerability occurs when Internet Explorer encounters maliciously crafted web pages that attempt to instantiate the vulnerable ActiveX controls. When these objects are loaded and executed, the browser's memory management routines fail to properly validate the parameters passed to the COM objects, resulting in buffer overflows, memory corruption, or other memory-related anomalies. This memory corruption can manifest as application crashes, memory leaks, or more critically, provide attackers with opportunities to inject and execute arbitrary code within the context of the browser process. The vulnerability is particularly dangerous because it leverages the trust relationship between the browser and Windows system components, allowing attackers to bypass normal security boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable full system compromise. When successfully exploited, attackers can execute arbitrary code with the privileges of the user running Internet Explorer, which typically corresponds to the local user account. This could lead to complete system compromise, data exfiltration, or the establishment of persistent backdoors. The vulnerability affects Windows 2000 systems specifically, which were commonly used in enterprise environments during the period when this vulnerability was prevalent. The memory corruption characteristics align with common software security weaknesses categorized under CWE-121, which deals with stack-based buffer overflows, and CWE-122, which addresses heap-based buffer overflows. The attack vector is classified as remote execution through web content, making it particularly dangerous for widespread deployment.
From a threat modeling perspective, this vulnerability maps to several ATT&CK techniques including T1059 for command and script interpreter usage, T1068 for exploit for privilege escalation, and T1203 for exploitation for execution. The vulnerability's exploitation typically follows a pattern of web-based delivery where attackers craft malicious websites or phishing emails containing HTML content that automatically triggers the instantiation of the vulnerable ActiveX controls. Mitigation strategies should include immediate deployment of Microsoft security patches, implementation of ActiveX control restrictions through group policies, and browser hardening measures such as disabling automatic ActiveX control loading. Network-based protections like web application firewalls can help detect and block exploitation attempts, while endpoint protection solutions should monitor for suspicious ActiveX control behavior. Organizations should also consider implementing sandboxing techniques and restricting user privileges to limit potential damage from successful exploitation attempts. The vulnerability highlights the importance of proper input validation and memory management in software development processes, aligning with security best practices outlined in the OWASP Top Ten and NIST cybersecurity frameworks.