CVE-2000-0073 in Windows
Summary
by MITRE
Buffer overflow in Microsoft Rich Text Format (RTF) reader allows attackers to cause a denial of service via a malformed control word.
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Analysis
by VulDB Data Team • 10/19/2025
The vulnerability identified as CVE-2000-0073 represents a critical buffer overflow flaw within Microsoft's Rich Text Format reader implementation. This issue specifically manifests when processing malformed control words within RTF documents, creating a condition where the application fails to properly validate input boundaries. The RTF format, widely used for document exchange across various Microsoft applications including Word and Outlook, becomes a vector for exploitation when encountering specially crafted control sequences that exceed allocated memory buffers. This vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows malicious data to overwrite adjacent memory locations.
The technical exploitation of this vulnerability occurs when an attacker crafts an RTF document containing an oversized control word that exceeds the predetermined buffer size allocated by the RTF parser. When the vulnerable application attempts to process this malformed document, the parser fails to validate the length of the control word, leading to memory corruption that can result in application termination or system instability. The buffer overflow typically manifests as a stack smashing condition where the excess data overwrites return addresses and other critical stack variables, potentially enabling arbitrary code execution in some scenarios though the primary impact documented is denial of service.
From an operational perspective, this vulnerability presents significant risks to enterprise environments where RTF documents are commonly exchanged through email systems, file sharing platforms, and collaborative applications. The attack vector is particularly dangerous because RTF files are often perceived as safe attachments, making them ideal for social engineering campaigns. The denial of service impact can disrupt business operations by rendering email clients and document processing applications unavailable, potentially affecting thousands of users within an organization. Organizations relying heavily on Microsoft Office suites and email systems face the highest risk of exploitation, as these applications are frequently targeted due to their widespread deployment and the ease with which malicious RTF documents can be distributed.
Mitigation strategies for CVE-2000-0073 should focus on immediate patch application from Microsoft, which addressed the buffer overflow by implementing proper input validation and boundary checking within the RTF parser. Network-level defenses can include RTF content filtering and sandboxing mechanisms that isolate document processing from core system resources. Additionally, security configurations should disable automatic RTF processing in email clients and implement strict file extension controls to prevent execution of potentially malicious RTF documents. The vulnerability demonstrates the importance of input validation practices aligned with secure coding standards and represents a classic example of why defensive programming techniques are essential in preventing buffer overflow exploits. Organizations should also consider implementing email security gateways that can detect and quarantine suspicious RTF content before it reaches end-user systems, providing an additional layer of protection against this and similar vulnerabilities.