CVE-2015-0743 in Headend System Release
Summary
by MITRE
Cisco Headend System Release allows remote attackers to cause a denial of service (DHCP and TFTP outage) via a flood of crafted UDP traffic, aka Bug ID CSCus04097.
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Analysis
by VulDB Data Team • 05/19/2022
The Cisco Headend System Release vulnerability identified as CVE-2015-0743 represents a critical denial of service weakness that affects network infrastructure components responsible for managing DHCP and TFTP services. This vulnerability manifests when the system receives an excessive volume of crafted UDP traffic, leading to complete service disruption across both DHCP and TFTP protocols. The flaw resides within the system's packet processing mechanisms, where insufficient input validation and rate limiting capabilities allow malicious actors to overwhelm the system's resources through carefully constructed network packets.
The technical implementation of this vulnerability stems from inadequate traffic handling within the Cisco Headend System's network processing stack. When the system encounters a flood of malformed UDP packets, particularly those targeting DHCP and TFTP ports, the device's processing capabilities become saturated, resulting in service degradation or complete outages. This behavior aligns with CWE-400, which categorizes unchecked resource consumption as a significant weakness in software systems. The vulnerability specifically impacts UDP port 67 (DHCP server) and port 68 (DHCP client) for DHCP services, along with UDP port 69 for TFTP services, making it particularly dangerous for network environments that rely heavily on these protocols for device provisioning and file transfers.
From an operational perspective, the impact of CVE-2015-0743 extends far beyond simple service interruption, as it can compromise entire network operations within organizations that depend on automated device provisioning and file distribution systems. Network administrators may experience complete loss of connectivity for devices attempting to obtain IP addresses through DHCP or request files via TFTP services. The vulnerability's remote exploitability means that attackers can initiate the attack from external network locations without requiring physical access or local credentials, making it particularly dangerous for enterprise environments. According to ATT&CK framework technique T1499.004, this vulnerability enables adversaries to perform network denial of service attacks, potentially disrupting business operations and creating security incident response challenges.
Mitigation strategies for this vulnerability should encompass both immediate defensive measures and long-term architectural improvements. Network segmentation and access control lists should be implemented to limit UDP traffic to essential ports, while rate limiting mechanisms can help prevent packet flooding attacks from overwhelming system resources. The Cisco recommended solution involves applying specific software patches that enhance input validation and implement proper traffic throttling for UDP packets. Organizations should also consider deploying intrusion detection systems that can identify and alert on unusual traffic patterns targeting DHCP and TFTP ports, providing early warning capabilities. Additionally, implementing redundant DHCP and TFTP services with proper load balancing can help maintain availability during potential attacks, while regular network monitoring and baseline traffic analysis can aid in quickly identifying anomalous behavior indicative of exploitation attempts. The vulnerability demonstrates the critical importance of proper resource management and input validation in network infrastructure systems, particularly those handling high-volume protocols like DHCP and TFTP that are fundamental to network operations.