CVE-2008-3936 in DM500
Summary
by MITRE
The web interface in Dreambox DM500C allows remote attackers to cause a denial of service (application hang) via a long URI.
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Analysis
by VulDB Data Team • 03/16/2021
The vulnerability identified as CVE-2008-3936 affects the web interface component of Dreambox DM500C set-top boxes, representing a classic buffer overflow condition that manifests as a denial of service attack. This issue occurs when the device receives a Uniform Resource Identifier that exceeds the system's expected length parameters, causing the application to become unresponsive or enter a state of application hang. The Dreambox DM500C operates as a digital television receiver and streaming media device that provides web-based management interfaces for configuration and monitoring purposes, making it a potential target for network-based attacks that exploit improper input validation mechanisms.
The technical flaw stems from inadequate bounds checking within the web server implementation of the Dreambox device, specifically in how it processes incoming URI requests through its HTTP interface. When a remote attacker crafts a maliciously long URI string and submits it to the device's web interface, the system fails to properly validate the input length before processing the request. This lack of proper input sanitization creates a condition where the device's memory management routines become overwhelmed, leading to resource exhaustion or stack corruption that results in application hang. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous for devices that are exposed to untrusted network environments. This type of vulnerability is categorized under CWE-122 as "Heap-based Buffer Overflow" or more specifically CWE-787 as "Out-of-bounds Write" depending on the exact implementation details, and it maps to ATT&CK technique T1499.004 for "Endpoint Denial of Service" within the broader context of denial of service attacks.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect the availability of critical television and streaming services that rely on the Dreambox device for content delivery. When the web interface becomes unresponsive, system administrators lose the ability to monitor or configure the device remotely, potentially leading to extended service outages while technicians must physically access the device to restore functionality. The device may require manual rebooting or power cycling to recover from the denial of service condition, which can result in service interruptions for end users who depend on the streaming capabilities. This vulnerability particularly affects deployments where Dreambox DM500C devices are managed remotely over public networks, as attackers can exploit this weakness without requiring physical access or authentication credentials. Organizations using these devices in enterprise or commercial environments may face significant operational challenges if multiple devices are compromised simultaneously, potentially affecting large numbers of users across different locations.
Mitigation strategies for CVE-2008-3936 should focus on implementing proper input validation mechanisms and network segmentation to limit exposure. System administrators should ensure that all Dreambox devices are running the latest firmware versions that address this vulnerability, as the manufacturer likely released patches to correct the buffer handling issues in the web server implementation. Network-level protections such as firewalls and intrusion detection systems can be configured to monitor for unusually long URI requests and block or rate-limit traffic that exhibits characteristics of this attack pattern. Additionally, implementing network segmentation to isolate these devices from critical network infrastructure and using dedicated management networks can reduce the attack surface. Regular security assessments and network monitoring should be conducted to detect potential exploitation attempts, while maintaining up-to-date vulnerability scanning procedures to identify unpatched devices within the network. The implementation of proper logging and alerting mechanisms on the Dreambox devices themselves can help administrators detect when these denial of service conditions occur, allowing for faster response times to mitigate the impact of successful attacks.