CVE-2017-10980 in FreeRADIUS
Summary
by MITRE
An FR-GV-203 issue in FreeRADIUS 2.x before 2.2.10 allows "DHCP - Memory leak in decode_tlv()" and a denial of service.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-10980 represents a critical memory management flaw within the FreeRADIUS authentication server software that affects versions prior to 2.2.10. This issue specifically manifests within the DHCP module's decode_tlv() function, where improper memory handling creates conditions that can lead to resource exhaustion and system instability. The vulnerability stems from inadequate memory allocation and deallocation practices during the processing of DHCP messages, particularly when handling TLV (Type-Length-Value) encoded data structures that are fundamental to DHCP protocol operations.
The technical flaw occurs when the decode_tlv() function processes malformed or specially crafted DHCP packets containing TLV elements that trigger memory allocation without proper subsequent deallocation. This memory leak accumulates over time as the FreeRADIUS server continues to process incoming DHCP requests, eventually consuming all available memory resources on the system. The vulnerability is particularly concerning because DHCP functionality is commonly enabled in FreeRADIUS deployments for network access control and wireless authentication scenarios, making it a frequent target for exploitation. The flaw aligns with CWE-401, which specifically addresses improper handling of memory allocation and deallocation, and represents a classic denial of service vector that can be easily exploited by remote attackers.
Operationally, this vulnerability creates significant risk for organizations relying on FreeRADIUS for network authentication services. Attackers can exploit the memory leak by sending specially crafted DHCP packets that trigger the vulnerable code path, leading to gradual memory consumption until the system becomes unresponsive or crashes entirely. This denial of service condition directly impacts network access control, potentially disrupting wireless networks, wired authentication systems, and any infrastructure that depends on FreeRADIUS for user authentication. The impact extends beyond simple service disruption as the memory leak can cause cascading failures in network infrastructure, affecting multiple services that depend on the affected FreeRADIUS server. Organizations using older FreeRADIUS versions in production environments face substantial risk of operational disruption, especially in high-traffic network environments where the memory consumption occurs more rapidly.
The recommended mitigation strategy involves immediate deployment of FreeRADIUS version 2.2.10 or later, which contains the necessary patches to address the memory leak in the DHCP module. System administrators should also implement network monitoring to detect unusual memory consumption patterns that might indicate exploitation attempts. Additional protective measures include implementing rate limiting on DHCP traffic, configuring firewall rules to restrict DHCP packet sources, and establishing robust monitoring for memory usage on FreeRADIUS servers. Organizations should also consider implementing intrusion detection systems that can identify patterns consistent with this specific vulnerability, as the memory leak behavior follows predictable patterns that can be detected through behavioral analysis. The vulnerability demonstrates the critical importance of keeping authentication infrastructure updated and highlights the need for comprehensive vulnerability management programs that address both known and emerging threats in network security systems. This issue represents a typical case where a seemingly minor memory management flaw can have severe operational consequences, emphasizing the importance of thorough code review and testing processes in security-critical software components.