CVE-2002-0026 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.5 and 6.0 allows remote attackers to bypass restrictions for executing scripts via an object that processes asynchronous events after the initial security checks have been made.
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Analysis
by VulDB Data Team • 06/27/2021
The vulnerability described in CVE-2002-0026 represents a critical security flaw in Microsoft Internet Explorer versions 5.5 and 6.0 that fundamentally undermines the browser's security model. This issue specifically targets the browser's handling of asynchronous script execution within objects, creating a window of opportunity for malicious actors to circumvent security restrictions that should normally prevent unauthorized code execution. The flaw exploits the timing gap between initial security validation and subsequent asynchronous event processing, allowing attackers to execute potentially harmful scripts that would otherwise be blocked by the browser's security mechanisms.
The technical nature of this vulnerability stems from how Internet Explorer manages object-oriented scripting environments and asynchronous event handling. When a web page loads, the browser performs initial security checks to determine whether script execution should be permitted based on the page's origin and security context. However, certain objects within the browser's scripting engine can process asynchronous events that occur after these initial checks have been completed. This creates a race condition where malicious code can be injected and executed during the brief period between the security validation and the asynchronous event processing phase. The vulnerability specifically affects the interaction between the browser's security model and its object model, particularly when dealing with components that can defer execution of script code.
The operational impact of this vulnerability is significant as it allows remote attackers to execute arbitrary code on vulnerable systems without requiring user interaction or specific exploitation conditions. Attackers can craft malicious web pages that appear legitimate to users while containing hidden script code that exploits this timing window to bypass security restrictions. This capability enables a range of malicious activities including credential theft, system compromise, and data exfiltration. The vulnerability affects users who visit compromised websites or click on malicious links, making it particularly dangerous in web-based attack scenarios where users have no direct control over the security context of the pages they visit.
This vulnerability aligns with several cybersecurity frameworks and classifications including CWE-118 which describes improper access to resources through object references, and relates to ATT&CK technique T1059.007 for command and scripting interpreter. The flaw demonstrates how asynchronous processing in web browsers can create security gaps that attackers can exploit through careful timing and code injection techniques. Organizations affected by this vulnerability should implement immediate mitigations including browser updates, security policy enforcement, and network-based protections. The recommended approach involves applying Microsoft security patches that address the specific timing issues in the browser's object model and asynchronous event handling, along with implementing additional security controls such as content filtering and user education about safe browsing practices to reduce the risk of exploitation.