CVE-2022-24705 in ACCEL-PPP
Summary
by MITRE • 02/15/2022
The rad_packet_recv function in radius/packet.c suffers from a memcpy buffer overflow, resulting in an overly-large recvfrom into a fixed buffer that causes a buffer overflow and overwrites arbitrary memory. If the server connects with a malicious client, crafted client requests can remotely trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/18/2022
The vulnerability identified as CVE-2022-24705 represents a critical buffer overflow flaw within the rad_packet_recv function of the FreeRADIUS server implementation. This issue resides in the radius/packet.c source file where the function processes incoming RADIUS packets through a recvfrom system call that reads data into a fixed-size buffer without proper bounds checking. The flaw stems from inadequate input validation that fails to account for packets exceeding the allocated buffer space, creating a scenario where maliciously crafted packets can trigger memory corruption. The vulnerability specifically affects the RADIUS protocol implementation used for network authentication and authorization services, making it particularly dangerous in enterprise environments where such services are extensively deployed. The buffer overflow occurs during packet reception when the system attempts to copy data from the network socket into a statically allocated buffer, without verifying that the incoming data length remains within acceptable limits.
The technical exploitation of this vulnerability follows a well-defined pattern that aligns with common buffer overflow attack methodologies. When a malicious client establishes a connection to the vulnerable FreeRADIUS server and sends a crafted packet, the system's recvfrom call reads data into a fixed-size buffer that is insufficient to accommodate the malicious payload. This overflow allows an attacker to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical program state information. The attack vector is particularly concerning because it requires only a single malicious client connection to trigger the vulnerability, making it suitable for remote exploitation without requiring elevated privileges. The memory corruption can lead to arbitrary code execution, service denial, or privilege escalation depending on how the corrupted memory is utilized by the application. This vulnerability directly maps to CWE-121, which describes stack-based buffer overflow conditions, and also aligns with CWE-787, describing out-of-bounds write conditions in heap-based buffers.
The operational impact of CVE-2022-24705 extends beyond simple service disruption to potentially enable full system compromise within environments utilizing FreeRADIUS for authentication services. Organizations relying on RADIUS for network access control, wireless authentication, or VPN access are at significant risk since the vulnerability can be exploited remotely by attackers who establish connections to the server. The attack requires minimal privileges and can be executed from any network location that can reach the vulnerable server, making it particularly dangerous in perimeter environments where RADIUS servers are exposed to external networks. Successful exploitation could allow attackers to execute arbitrary code with the privileges of the FreeRADIUS service account, potentially leading to complete system compromise. The vulnerability also impacts network infrastructure security since RADIUS servers often serve as critical authentication points for enterprise networks, making them attractive targets for attackers seeking to gain persistent access or escalate privileges. This aligns with ATT&CK technique T1566, which covers phishing with malicious attachments or links, but in this case the attack vector is direct network connection rather than social engineering.
Mitigation strategies for CVE-2022-24705 should prioritize immediate patch application from the FreeRADIUS vendor, as this represents a critical vulnerability requiring urgent attention. Organizations should also implement network segmentation to limit direct access to RADIUS servers from untrusted networks and deploy intrusion detection systems to monitor for suspicious packet patterns that might indicate exploitation attempts. Additional protective measures include implementing strict access controls for RADIUS server communication, enabling network monitoring for unusual traffic patterns, and conducting regular security assessments of authentication infrastructure. The vulnerability demonstrates the importance of proper input validation and bounds checking in network protocol implementations, highlighting the need for robust defensive programming practices. Security teams should also consider implementing automated patch management processes to ensure timely deployment of security updates and maintain detailed inventory of all RADIUS server deployments within their environments. Organizations may also benefit from implementing network access control lists to restrict which systems can communicate with RADIUS servers, reducing the attack surface and limiting potential exploitation scenarios.