CVE-2006-5196 in SURFboard
Summary
by MITRE
The HTTP interface in the Motorola SURFboard SB4200 Cable Modem allows remote attackers to cause a denial of service (device crash) via a request with MfcISAPICommand set to SecretProc and a long string in the Secret parameter.
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Analysis
by VulDB Data Team • 04/23/2026
The vulnerability identified as CVE-2006-5196 affects the Motorola SURFboard SB4200 Cable Modem's HTTP interface, representing a critical security flaw that enables remote attackers to execute denial of service attacks against the device. This vulnerability resides within the modem's web-based management interface, which serves as a primary point of access for network administrators to configure and monitor the device's operations. The flaw specifically manifests when the MfcISAPICommand parameter is set to SecretProc, triggering a particular processing path within the modem's software architecture that fails to properly handle input validation.
The technical implementation of this vulnerability stems from insufficient input sanitization and boundary checking within the modem's HTTP request processing logic. When an attacker crafts a request with the MfcISAPICommand parameter set to SecretProc and includes an excessively long string in the Secret parameter, the device's processing routine fails to properly validate the input length or handle the buffer allocation. This leads to a buffer overflow condition or memory corruption that ultimately results in the device crashing and becoming unavailable to legitimate users. The vulnerability operates at the application layer of the network stack, making it accessible over the network without requiring authentication or physical access to the device.
The operational impact of this vulnerability extends beyond simple device unavailability, as it can disrupt internet connectivity for all users relying on the affected modem. Network administrators may experience significant downtime while attempting to restore service, and the vulnerability can be exploited by malicious actors to create persistent service disruptions. The attack vector is particularly concerning because it requires no authentication credentials, making it accessible to anyone who can reach the modem's HTTP interface over the network. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation that can lead to system instability.
Mitigation strategies for this vulnerability should include immediate firmware updates from Motorola to address the buffer handling issues in the HTTP interface. Network segmentation and access control measures can help reduce exposure by limiting access to the modem's administrative interface to trusted network segments only. Implementing network monitoring solutions that can detect unusual traffic patterns or malformed HTTP requests may provide early warning of exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and input validation, particularly for network-facing applications. Organizations should also consider implementing network access control lists to restrict access to the modem's HTTP management interface and ensure that only authorized personnel can access these administrative functions. This vulnerability exemplifies the broader category of vulnerabilities classified under the ATT&CK framework's privilege escalation and denial of service techniques, highlighting the need for comprehensive security measures throughout the network infrastructure.