CVE-2006-3427 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 allows remote attackers to cause a denial of service (crash) by declaring the sourceURL attribute on an uninitialized DirectAnimation.StructuredGraphicsControl ActiveX Object, which triggers a null dereference.
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Analysis
by VulDB Data Team • 04/07/2017
This vulnerability resides in Microsoft Internet Explorer 6's handling of ActiveX controls, specifically the DirectAnimation.StructuredGraphicsControl object. The flaw manifests when an attacker crafts a malicious web page that declares a sourceURL attribute on an uninitialized ActiveX object. This particular implementation fails to properly validate the object state before attempting to process the sourceURL parameter, leading to a critical null pointer dereference condition. The vulnerability represents a classic buffer over-read scenario where the application attempts to access memory location zero, which is not accessible, resulting in an immediate application crash and subsequent denial of service for the user.
The technical exploitation of this vulnerability aligns with CWE-476, which describes null pointer dereference conditions in software implementations. This weakness specifically affects the object lifecycle management within Internet Explorer's ActiveX handling subsystem, where uninitialized objects are not properly validated before attribute assignment operations. The attack vector operates through web content delivery, making it particularly dangerous as users can be exploited simply by visiting a malicious website. The vulnerability demonstrates poor input validation and object state management practices that violate fundamental security principles outlined in the OWASP Top Ten and other industry standards.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged in more sophisticated attacks within a broader exploitation framework. When combined with other vulnerabilities or used as a preliminary step in attack chains, this denial of service condition can serve as a precursor to more severe exploits. The vulnerability affects all versions of Internet Explorer 6 that support DirectAnimation controls, making it particularly concerning given the widespread deployment of this browser version during the affected period. From an attacker perspective, this represents a low-effort, high-impact method for disrupting user sessions and potentially creating conditions for more advanced attacks.
Mitigation strategies for this vulnerability include immediate patch deployment through Microsoft's security update process, which addresses the null pointer dereference by implementing proper object validation before attribute processing. Organizations should also implement browser hardening measures such as disabling ActiveX controls, implementing content security policies, and deploying web application firewalls to filter malicious content. The vulnerability highlights the importance of proper object initialization and validation practices in browser security architectures, aligning with ATT&CK technique T1203 for legitimate credentials and T1059 for command and scripting interpreter usage. Network administrators should consider implementing browser isolation techniques and monitoring for anomalous ActiveX object behavior as part of their defensive posture. Additionally, user education regarding safe browsing practices and the risks associated with visiting untrusted websites remains crucial in mitigating the broader threat landscape surrounding such vulnerabilities.