CVE-2009-0553 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 SP1, 6 and 7 on Windows XP SP2 and SP3, 6 and 7 on Windows Server 2003 SP1 and SP2, 7 on Windows Vista Gold and SP1, and 7 on Windows Server 2008 allows remote attackers to execute arbitrary code via a web page that triggers presence of an object in memory that was (1) not properly initialized or (2) deleted, aka "Uninitialized Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2025
This vulnerability represents a critical memory corruption issue affecting multiple versions of Microsoft Internet Explorer across various Windows operating systems. The flaw occurs when Internet Explorer processes web content that contains objects in memory which have not been properly initialized or have been deleted, creating a condition where malicious code can be executed remotely. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, though specifically manifests as uninitialized memory corruption within the browser's memory management system. The vulnerability is particularly dangerous because it allows remote attackers to execute arbitrary code with the privileges of the logged-in user, potentially leading to complete system compromise.
The technical mechanism behind this vulnerability involves Internet Explorer's handling of memory objects that should have been properly allocated and initialized but instead remain in an undefined state. When the browser attempts to access these uninitialized or deleted objects, it can lead to memory corruption that attackers can manipulate to redirect execution flow. This type of memory corruption vulnerability is classified as a heap-based buffer overflow in threat modeling frameworks, where the attacker can overwrite critical memory locations to inject and execute malicious code. The vulnerability specifically affects the browser's object model handling, where JavaScript or ActiveX components may reference memory that was previously freed or never properly allocated, creating exploitable conditions.
The operational impact of this vulnerability is severe as it enables remote code execution without user interaction, making it particularly dangerous in enterprise environments where users may browse untrusted websites. Attackers can craft malicious web pages that exploit this condition to install backdoors, steal sensitive data, or establish persistent access to compromised systems. The vulnerability affects widely deployed versions of Internet Explorer, including IE6 SP1, IE6, IE7 on various Windows XP and Server 2003 configurations, as well as IE7 on Vista and Server 2008 systems. This broad impact scope makes it a high-priority target for attackers seeking to exploit the largest possible attack surface. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) techniques, as it allows for remote code execution and privilege escalation.
Mitigation strategies for this vulnerability should focus on immediate patch deployment, as Microsoft released security updates addressing this specific memory corruption issue. Organizations should implement browser hardening measures including disabling unnecessary ActiveX controls, implementing sandboxing mechanisms, and using security features like Internet Explorer's protected mode. Network-level protections such as firewalls and web application firewalls can help reduce exposure by filtering malicious content. Additionally, user education regarding safe browsing practices and awareness of social engineering tactics that may accompany such exploits is crucial. Regular security assessments and vulnerability scanning should be conducted to identify systems running vulnerable versions of Internet Explorer. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that reduce the attack surface available to potential exploiters.