CVE-2000-0765 in Word
Summary
by MITRE
Buffer overflow in the HTML interpreter in Microsoft Office 2000 allows an attacker to execute arbitrary commands via a long embedded object tag, aka the "Microsoft Office HTML Object Tag" vulnerability.
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Analysis
by VulDB Data Team • 06/05/2019
The CVE-2000-0765 vulnerability represents a critical buffer overflow flaw in Microsoft Office 2000's HTML interpreter component that fundamentally compromises system security through malformed HTML content. This vulnerability specifically targets the processing of embedded object tags within HTML documents, creating a pathway for remote code execution that has significant implications for enterprise environments. The flaw exists in how Office 2000 handles HTML parsing, particularly when encountering excessively long embedded object tags that exceed the allocated buffer space, leading to memory corruption that attackers can exploit to gain unauthorized system access.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within Office 2000's HTML processing engine. When a user opens a maliciously crafted document containing an embedded object tag with excessive length, the application fails to properly bounds-check the input data before copying it into fixed-size memory buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially corrupting the program's execution flow and enabling arbitrary code execution with the privileges of the affected user. The vulnerability operates at the application layer and can be triggered through various attack vectors including email attachments, web downloads, or network shares, making it particularly dangerous in enterprise environments where users frequently open documents from untrusted sources.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on Microsoft Office 2000, as it enables attackers to execute malicious code remotely without requiring user interaction beyond opening a compromised document. The attack surface extends beyond individual workstations to potentially compromise entire network infrastructures, as successful exploitation can lead to privilege escalation, lateral movement, and data exfiltration. The vulnerability is particularly concerning because it can be exploited through social engineering techniques, where users are tricked into opening seemingly legitimate documents that contain the malicious embedded object tags. Organizations using older Office versions face heightened risk as patches for this vulnerability were not widely available during the time of its discovery, leaving many systems vulnerable to exploitation.
Mitigation strategies for CVE-2000-0765 should prioritize immediate system hardening through software updates and security patches provided by Microsoft, though organizations may need to implement additional protective measures given the age of the affected software. Network segmentation and email filtering solutions can help reduce the attack surface by preventing malicious documents from reaching end users, while application whitelisting can restrict execution of untrusted Office documents. Security monitoring should focus on detecting unusual document opening patterns and memory access anomalies that may indicate exploitation attempts. Organizations should also consider implementing mandatory security awareness training to reduce the likelihood of successful social engineering attacks that leverage this vulnerability, as user behavior remains a critical factor in successful exploitation. This vulnerability aligns with CWE-121 and CWE-122 categories related to buffer overflow conditions and improper input validation, and it maps to ATT&CK technique T1203 for Exploitation for Execution, highlighting the need for comprehensive defensive strategies across multiple security domains.
The broader implications of this vulnerability extend beyond immediate exploitation to demonstrate the critical importance of secure coding practices and regular software maintenance in enterprise security. Legacy systems running vulnerable versions of Microsoft Office require special attention and may need to be upgraded or isolated from critical network resources to prevent exploitation. Security professionals should implement robust vulnerability management processes that include regular assessment of legacy software components, as vulnerabilities like CVE-2000-0765 often remain unpatched in older systems and create persistent security risks that can be exploited for extended periods. The vulnerability serves as a historical example of how seemingly minor input validation flaws can result in catastrophic security consequences, emphasizing the need for rigorous security testing and code review processes throughout the software development lifecycle.