CVE-2017-10979 in FreeRADIUS
Summary
by MITRE
An FR-GV-202 issue in FreeRADIUS 2.x before 2.2.10 allows "Write overflow in rad_coalesce()" - this allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-10979 represents a critical write overflow condition within the FreeRADIUS authentication server software version 2.x prior to 2.2.10. This issue specifically affects the rad_coalesce() function which is responsible for processing and coalescing network packets during the authentication process. The flaw exists in the handling of packet data structures where insufficient bounds checking allows malicious input to overwrite adjacent memory regions. This write overflow vulnerability falls under the CWE-121 category of stack-based buffer overflow, though it manifests as a more complex memory corruption issue that can occur in heap or data segment memory regions. The vulnerability is particularly dangerous because it operates within the core packet processing functionality of the RADIUS daemon, making it accessible to remote attackers who can craft malicious packets to trigger the condition.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution on affected systems. When a remote attacker sends specially crafted packets to a vulnerable FreeRADIUS server, the write overflow in rad_coalesce() can cause the daemon to crash immediately or corrupt memory in a way that allows arbitrary code execution. This attack vector is particularly concerning because RADIUS servers typically operate in network infrastructure environments where they are exposed to untrusted network traffic and may be running with elevated privileges. The vulnerability affects the daemon's ability to process authentication requests, which can lead to complete service disruption and potentially provide attackers with persistent access to network resources. The exploitability of this vulnerability is enhanced by the fact that RADIUS servers are commonly deployed in environments where they must accept and process packets from unauthenticated sources, making the attack surface particularly broad.
Mitigation strategies for CVE-2017-10979 should prioritize immediate patching of affected FreeRADIUS installations to version 2.2.10 or later, which contains the necessary fixes for the memory corruption issue. Organizations should also implement network segmentation and access controls to limit exposure of RADIUS servers to untrusted networks, applying the principle of least privilege to reduce potential attack vectors. Additional defensive measures include implementing network monitoring to detect unusual packet patterns that might indicate exploitation attempts, configuring intrusion detection systems to flag malformed RADIUS packets, and establishing robust logging mechanisms to track authentication requests and potential exploitation attempts. From an operational security perspective, system administrators should regularly audit their network infrastructure to identify all RADIUS server implementations and ensure they are properly updated and configured. The vulnerability demonstrates the importance of proper input validation and bounds checking in network services, aligning with ATT&CK technique T1203 for legitimate credentials and T1059 for command and scripting interpreter execution. Organizations should also consider implementing network access control lists and firewall rules to restrict access to RADIUS ports (typically UDP 1812 and 1813) to only trusted sources, reducing the attack surface and limiting the potential impact of such vulnerabilities in their network infrastructure.