CVE-2000-0929 in Windows Media Player
Summary
by MITRE
Microsoft Windows Media Player 7 allows attackers to cause a denial of service in RTF-enabled email clients via an embedded OCX control that is not closed properly, aka the "OCX Attachment" vulnerability.
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Analysis
by VulDB Data Team • 06/03/2025
The CVE-2000-0929 vulnerability represents a critical denial of service flaw affecting Microsoft Windows Media Player 7 within RTF-enabled email clients. This vulnerability specifically targets the improper handling of embedded OCX controls, creating a pathway for attackers to disrupt normal system operations through carefully crafted email attachments. The issue stems from the way Windows Media Player processes embedded ActiveX controls within Rich Text Format documents, particularly when these controls are not properly closed or released from memory after initial execution.
The technical mechanism behind this vulnerability involves the improper resource management within the Windows Media Player component when processing RTF documents containing malicious OCX references. When an email client processes an RTF message containing an embedded OCX control that points to Windows Media Player, the player fails to properly close or release the control instance, leading to resource exhaustion and ultimately causing the affected application or system to become unresponsive. This behavior aligns with CWE-404, which describes improper resource management, and specifically relates to improper cleanup of ActiveX controls. The vulnerability operates at the application layer, exploiting weaknesses in how email clients handle embedded multimedia components within rich text documents.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged to create persistent system instability within email environments. Attackers can craft malicious RTF emails that, when opened by vulnerable systems, trigger the improper OCX control handling, causing the email client to freeze or crash repeatedly. This creates a cascading effect where users cannot access their email communications, and system administrators must intervene to restore normal operations. The vulnerability particularly affects organizations relying on RTF-enabled email clients such as Microsoft Outlook, which was commonly used in enterprise environments during this period. The attack surface is broad due to the widespread adoption of Windows Media Player and email clients that support RTF formatting, making this vulnerability particularly dangerous for networked environments.
Mitigation strategies for CVE-2000-0929 require a multi-layered approach combining immediate patching with defensive configuration changes. Microsoft released patches for Windows Media Player 7 that addressed the improper resource handling of embedded OCX controls, and organizations should prioritize deployment of these updates. Network administrators should implement email filtering rules that block or quarantine RTF attachments from untrusted sources, while also configuring email clients to disable automatic execution of embedded objects. The ATT&CK framework categorizes this vulnerability under T1204.002, which covers "User Execution: Malicious File," emphasizing the importance of user awareness training and email security controls. Additional protective measures include disabling ActiveX controls in email clients, implementing sandboxing techniques for email processing, and establishing monitoring protocols to detect unusual resource consumption patterns that might indicate exploitation attempts. Organizations should also consider implementing email security appliances that can analyze RTF content for malicious embedded objects before delivery to end users, creating an additional defensive barrier against this class of vulnerability.