CVE-2006-5581 in Internet Explorer
Summary
by MITRE
Unspecified vulnerability in Microsoft Internet Explorer 6 allows remote attackers to execute arbitrary code via certain DHTML script functions, such as normalize, and "incorrectly created elements" that trigger memory corruption, aka "DHTML Script Function Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 06/15/2025
This vulnerability resides within Microsoft Internet Explorer 6's handling of Dynamic HTML script functions, specifically targeting memory corruption mechanisms that occur during element creation and manipulation processes. The flaw manifests when certain DHTML functions such as normalize are invoked, creating incorrectly structured elements that subsequently trigger memory corruption conditions. This represents a classic buffer overflow scenario where improper memory management during dynamic element construction allows attackers to inject malicious code into the browser's memory space. The vulnerability operates at the core of Internet Explorer's rendering engine, exploiting weaknesses in how the browser processes and manages dynamic HTML content through script functions that manipulate DOM elements.
The technical execution of this vulnerability follows a memory corruption pattern that aligns with common software security flaws categorized under CWE-121, which deals with stack-based buffer overflow conditions. Attackers can craft malicious web pages containing specially constructed DHTML elements that, when processed by IE6, cause the browser to allocate memory incorrectly, leading to overwrite operations that can be exploited to execute arbitrary code with the privileges of the logged-in user. This memory corruption occurs during the normalization process of DHTML elements, where the browser's internal handling of element creation and manipulation fails to properly validate or sanitize input parameters, creating opportunities for code injection through malformed script function calls.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete system compromise capabilities within the context of the browser's security model. When successfully exploited, the vulnerability allows attackers to bypass typical security boundaries and execute malicious payloads that can escalate privileges, install backdoors, or perform other malicious activities. This vulnerability is particularly dangerous in enterprise environments where IE6 may still be in use, as it can be leveraged to establish persistent access to corporate networks through drive-by downloads or malicious web content. The attack vector requires only that a user visits a compromised web page, making it highly effective for widespread exploitation.
Mitigation strategies for this vulnerability center around immediate patching and browser upgrades, as Microsoft released security updates specifically addressing this memory corruption issue. Organizations should implement comprehensive browser lifecycle management policies that ensure all systems are running supported browser versions with current security patches. Network-based protections such as web application firewalls and content filtering solutions can provide additional layers of defense by blocking access to known malicious domains and content. Security monitoring should focus on detecting anomalous browser behavior and memory access patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving exploitation of software vulnerabilities and privilege escalation, making it a critical target for both preventive security measures and incident response preparedness. The vulnerability also highlights the importance of maintaining up-to-date security patches and implementing robust browser security configurations to prevent exploitation of legacy software components.