CVE-2002-2101 in Outlook
Summary
by MITRE
Microsoft Outlook 2002 allows remote attackers to execute arbitrary JavaScript code, even when scripting is disabled, via an "about:" or "javascript:" URI in the href attribute of an "a" tag.
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Analysis
by VulDB Data Team • 07/08/2024
This vulnerability exists in Microsoft Outlook 2002 where the email client fails to properly sanitize hyperlinks containing javascript protocols even when scripting is disabled. The flaw specifically affects the handling of href attributes within anchor tags, allowing malicious actors to embed javascript: or about: URIs that can execute arbitrary code when users click on the links. The vulnerability represents a critical security issue because it bypasses the intended security mechanism of script disabling, which is a fundamental protection against cross-site scripting attacks. This behavior violates the principle of least privilege and demonstrates a failure in input validation and sanitization.
The technical implementation of this vulnerability stems from Outlook 2002's insufficient filtering of URI schemes within HTML content. When processing email messages containing HTML elements, the application does not adequately distinguish between safe and dangerous URI protocols, particularly those that could execute code regardless of the scripting environment settings. The vulnerability is categorized under CWE-79 as a Cross-Site Scripting (XSS) flaw, specifically involving improper neutralization of special elements used in an OS command, where the special elements are javascript: URIs. This represents a failure in the application's security model to enforce proper input validation and output encoding.
From an operational perspective, this vulnerability enables remote code execution attacks that can compromise user systems without requiring any special privileges or complex exploitation techniques. Attackers can craft malicious emails that appear legitimate and when recipients click on seemingly harmless links, the embedded javascript code executes within the Outlook environment. This creates a significant risk for enterprise environments where users may not be security-aware and could inadvertently trigger the malicious code execution. The vulnerability affects the confidentiality, integrity, and availability of user data and systems, as attackers can potentially install malware, steal credentials, or access sensitive information.
The attack surface for this vulnerability is primarily email-based and exploits the trust users place in email content. According to ATT&CK framework, this represents a technique categorized under T1566 - Phishing and T1059 - Command and Scripting Interpreter, specifically targeting the user interaction phase of the attack lifecycle. The vulnerability is particularly dangerous because it operates outside normal security boundaries, allowing attackers to leverage the email client's processing environment to execute malicious code. Organizations should implement email filtering solutions that can detect and block javascript: URIs in email content, maintain updated security patches, and educate users about the risks of clicking on suspicious links. The vulnerability also highlights the importance of proper input validation and the need for applications to implement defense-in-depth strategies that protect against protocol-based attacks regardless of user settings or security configurations.