CVE-2008-3794 in VLC Media Player
Summary
by MITRE
Integer signedness error in the mms_ReceiveCommand function in modules/access/mms/mmstu.c in VLC Media Player 0.8.6i allows remote attackers to execute arbitrary code via a crafted mmst link with a negative size value, which bypasses a size check and triggers an integer overflow followed by a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability identified as CVE-2008-3794 represents a critical integer signedness error within the multimedia streaming module of VLC Media Player version 0.8.6i. This flaw exists in the mms_ReceiveCommand function located in the modules/access/mms/mmstu.c source file, where improper handling of size parameters creates a pathway for remote code execution. The vulnerability specifically targets the Media Message Streaming protocol implementation that VLC uses to handle streaming media content from Microsoft's streaming protocol. The flaw manifests when processing crafted mmst links that contain negative size values, which should never occur in legitimate streaming scenarios but can be exploited by malicious actors to manipulate the application's memory management routines.
The technical exploitation of this vulnerability begins with the manipulation of size parameters within the streaming protocol handling code. When VLC encounters a negative size value in a crafted mmst link, the integer signedness error causes the application to bypass crucial size validation checks that are designed to prevent buffer overflows. This bypass occurs because the application treats the negative value as a valid size parameter, leading to an integer overflow condition when the value is processed in subsequent calculations. The overflow condition creates a scenario where the application attempts to allocate memory blocks of invalid sizes, ultimately resulting in a heap-based buffer overflow that can be leveraged by attackers to execute arbitrary code on the target system.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a fundamental flaw in how VLC handles streaming protocol data validation. Attackers can craft malicious mmst links that exploit the integer overflow to manipulate heap memory layout, potentially leading to privilege escalation or system compromise. The vulnerability's remote nature means that attackers can exploit it without requiring local access to the target system, making it particularly dangerous in environments where users might unknowingly click on malicious links in emails, web pages, or instant messaging applications. This type of vulnerability falls under CWE-190, which specifically addresses integer overflow conditions, and demonstrates how improper input validation can lead to severe memory corruption issues.
The exploitation of CVE-2008-3794 aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution, as it involves leveraging a software vulnerability to execute arbitrary code on a target system. The vulnerability's characteristics make it particularly suitable for use in phishing campaigns or malicious website content, where attackers can embed the crafted mmst links in web pages or email attachments. The memory corruption aspects of this vulnerability also align with ATT&CK technique T1068, which addresses Exploitation for Privilege Escalation, as successful exploitation can potentially grant attackers elevated privileges on the compromised system. Organizations using VLC Media Player should be aware that this vulnerability affects not only the media player itself but also any applications that rely on VLC's streaming capabilities or that might process mmst links through VLC's underlying libraries.
Mitigation strategies for this vulnerability require immediate patching of VLC Media Player to version 0.8.7 or later, where the integer signedness error has been corrected through proper input validation and size parameter handling. System administrators should also implement network-level filtering to block mmst protocol traffic unless absolutely necessary, as this prevents the exploitation of the vulnerability through network-based attacks. Additionally, user education regarding the dangers of clicking on untrusted links or downloading content from unknown sources remains crucial, as this vulnerability can be exploited through social engineering attacks that trick users into launching malicious mmst links. The vulnerability demonstrates the importance of proper integer handling in security-critical applications and serves as a reminder that even seemingly minor programming errors can lead to severe security consequences. Organizations should also consider implementing application whitelisting policies that restrict the execution of media players or streaming applications to prevent unauthorized code execution, particularly in enterprise environments where such vulnerabilities could be exploited to gain access to sensitive information or compromise entire networks.