Source: cve@mitre.org
Livingston RADIUS code has a buffer overflow which can allow remote execution of commands as root.
Critical vulnerability discovered in Livingston RADIUS code allows for remote code execution (RCE). Successful exploitation grants attackers root-level privileges, enabling complete system compromise. This vulnerability, dating back to 1997, poses a significant risk to any systems still running vulnerable versions of Livingston RADIUS.
Step 1: Target Identification: The attacker identifies a system running a vulnerable version of Livingston RADIUS. Step 2: Payload Crafting: The attacker crafts a malicious RADIUS authentication request. This request includes a specially crafted attribute, such as a username or password, designed to overflow a buffer. The payload is designed to overwrite the stack and redirect execution to shellcode. Step 3: Request Submission: The attacker sends the malicious RADIUS authentication request to the targeted server. Step 4: Buffer Overflow Trigger: The vulnerable Livingston RADIUS code processes the malicious request. The overly long attribute overflows the allocated buffer. Step 5: Code Execution Hijack: The buffer overflow overwrites the return address on the stack. The overwritten return address points to the attacker's injected shellcode. Step 6: Shellcode Execution: The Livingston RADIUS process jumps to the attacker's shellcode, which executes with root privileges. Step 7: System Compromise: The shellcode grants the attacker a root shell, allowing complete control over the compromised system.
The vulnerability is a classic buffer overflow in the Livingston RADIUS code. The root cause lies in the mishandling of user-supplied input, likely within the processing of authentication requests. Specifically, the code fails to properly validate the length of data received from a remote client, such as an authentication request. When a specially crafted request containing an overly long string is sent, it overwrites adjacent memory buffers on the stack. This overwriting can overwrite critical data, including function return addresses, allowing an attacker to redirect program execution to arbitrary code, effectively achieving RCE. The lack of input validation and bounds checking is the fundamental flaw.
Due to the age of the vulnerability, it's unlikely to be directly associated with specific APT groups. However, any threat actor seeking to compromise legacy systems would likely leverage this vulnerability. The CISA KEV database does not list this specific CVE, but it is important to note that the age of the vulnerability and the potential for root access makes it a high-value target for any attacker.
Network traffic analysis: Examine RADIUS authentication traffic for unusually long attribute values, especially in username or password fields.
Log analysis: Review RADIUS server logs for suspicious activity, such as failed authentication attempts followed by successful ones, or unexpected errors.
Host-based intrusion detection systems (HIDS): Monitor for suspicious process behavior, such as unexpected processes spawned by the RADIUS server or unusual file modifications.
File integrity monitoring: Detect any unauthorized modifications to RADIUS server binaries or configuration files.
SIEM integration: Correlate network and host-based events to identify potential exploitation attempts.
Patching: The primary remediation is to upgrade to a patched version of Livingston RADIUS or a replacement RADIUS server that is not vulnerable. If patching is not possible, implement the following mitigations.
Network Segmentation: Isolate the RADIUS server from other critical network segments to limit the impact of a successful compromise.
Input Validation: Implement robust input validation at the RADIUS server to prevent buffer overflows. This includes checking the length and format of all incoming data.
Least Privilege: Run the RADIUS server with the least privileges necessary. This can limit the impact of a successful exploit.
Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities.
Intrusion Detection/Prevention Systems: Deploy and maintain intrusion detection and prevention systems to monitor for and block malicious activity.