CVE-2000-0061 in Internet Explorer
Summary
by MITRE
Internet Explorer 5 does not modify the security zone for a document that is being loaded into a window until after the document has been loaded, which could allow remote attackers to execute Javascript in a different security context while the document is loading.
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Analysis
by VulDB Data Team • 05/30/2025
The vulnerability described in CVE-2000-0061 represents a critical security flaw in Internet Explorer 5 that stems from improper handling of security zones during document loading processes. This issue specifically affects how the browser manages security contexts when loading web content, creating a window of opportunity for malicious actors to exploit temporal inconsistencies in the security model. The flaw manifests when Internet Explorer fails to establish the correct security zone boundaries for a document before the loading process completes, allowing attackers to manipulate JavaScript execution contexts during the transitional period.
This vulnerability operates under the principle of race condition exploitation within the browser's security architecture, where the timing of security context assignment creates an exploitable gap. The technical implementation involves the browser's document loading sequence where security zone information is not applied until after the document has already begun executing, potentially allowing malicious JavaScript code to run with elevated privileges or in a different security context than intended. This behavior violates fundamental security principles of least privilege and proper isolation between different security zones such as Internet, Local Intranet, and Trusted Sites.
The operational impact of CVE-2000-0061 extends beyond simple privilege escalation, as it enables attackers to bypass security restrictions that should normally prevent cross-zone script execution. During the brief window between document loading and security zone assignment, malicious code can execute JavaScript that would otherwise be restricted based on the document's intended security context. This vulnerability is particularly dangerous because it allows attackers to execute arbitrary code in contexts where they would normally be blocked by security policies, potentially leading to complete system compromise through techniques such as cross-site scripting attacks or privilege escalation exploits.
From a cybersecurity perspective, this vulnerability aligns with CWE-284 (Improper Access Control) and represents a classic case of temporal security weakness in browser architecture. The flaw demonstrates how browser security models can be undermined when implementation details fail to account for the temporal aspects of document processing and security context management. The attack vector typically involves hosting malicious content on a web server that can manipulate the loading sequence to exploit the time window where security zones have not yet been properly established. This vulnerability also maps to ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript) as it enables unauthorized JavaScript execution in inappropriate security contexts.
Mitigation strategies for CVE-2000-0061 require immediate browser updates and patches from Microsoft, as the vulnerability exists at the core browser architecture level. Organizations should implement network-level protections such as web application firewalls and content filtering systems to block known malicious content. Browser security policies should be configured to enforce strict zone isolation, and users should be educated about the risks of visiting untrusted websites. Additionally, implementing proper security zone configurations and ensuring that all users are running patched versions of Internet Explorer can effectively eliminate this vulnerability. The fix typically involves modifying the browser's document loading sequence to properly establish security contexts before any document execution begins, preventing the race condition that enables the exploit.