CVE-2003-0712 in Exchange
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the HTML encoding for the Compose New Message form in Microsoft Exchange Server 5.5 Outlook Web Access (OWA) allows remote attackers to execute arbitrary web script.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability identified as CVE-2003-0712 represents a critical cross-site scripting flaw within Microsoft Exchange Server 5.5 Outlook Web Access component. This security weakness specifically affects the HTML encoding implementation in the Compose New Message form, creating an exploitable condition that enables remote attackers to inject malicious scripts into web pages viewed by other users. The vulnerability resides in the server-side processing of user input within the web-based email interface, where insufficient sanitization of message content allows attacker-controlled data to bypass security controls and execute within the context of other users' browsers.
The technical exploitation of this vulnerability occurs through the improper handling of HTML characters during the rendering of email messages within the OWA interface. When users compose new messages through the web access portal, the system fails to adequately encode special HTML characters that could be used to construct malicious script payloads. This weakness falls under the CWE-79 category of Cross-Site Scripting, specifically representing a failure to properly encode output that enables attackers to inject client-side scripts. The vulnerability is particularly dangerous because it operates at the presentation layer where user-generated content is rendered, allowing attackers to execute arbitrary code within the victim's browser context with the privileges of the authenticated user.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable full account compromise and privilege escalation within the Exchange environment. Attackers can leverage this weakness to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users including reading, modifying, or deleting email messages. The attack vector requires no special privileges to initiate, making it particularly dangerous as it can be exploited by anyone with access to the vulnerable Exchange server. This vulnerability directly aligns with ATT&CK technique T1566.001 for Initial Access through spearphishing attachments and T1059.007 for Command and Scripting Interpreter using JavaScript, demonstrating how a single XSS flaw can enable multiple attack pathways within a network environment.
Mitigation strategies for CVE-2003-0712 should focus on immediate implementation of input validation and output encoding controls within the Exchange Server environment. Organizations must ensure that all user-supplied data is properly encoded before being rendered in web interfaces, implementing strict HTML sanitization routines that prevent script execution within message content. Microsoft released patches for this vulnerability as part of their regular security updates, and organizations should immediately apply the appropriate security rollups for Exchange Server 5.5. Additional protective measures include implementing web application firewalls to detect and block malicious script payloads, configuring proper content security policies, and conducting regular security assessments of web-based email interfaces to identify similar encoding vulnerabilities. Network segmentation and privileged access controls should also be enforced to limit the potential damage from successful exploitation attempts.