Radius/UDP. How legacy protocols need to keep up with modern cryptography

Researchers have discovered an improved attack against the MD5 cryptographic hash function, specifically affecting the RADIUS/UDP protocol commonly used for authentication in networking environments. This attack allows a malicious actor with access to RADIUS traffic to gain unauthorized administrative access to devices using RADIUS for authentication, without the need to steal passwords or shared secrets. The vulnerability lies in the outdated cryptographic constructions based on MD5 still present in RADIUS deployments. Despite advancements in cryptography, RADIUS continues to rely on MD5, making it susceptible to exploitation. The attack, known as Blast-RADIUS, leverages weaknesses in MD5 to manipulate RADIUS messages, enabling unauthorized access to networked devices. While protocols like HMAC-MD5 offer more secure alternatives, they are often optional in RADIUS configurations. The research highlights the importance of updating legacy protocols like RADIUS to mitigate security risks posed by evolving cryptographic attacks.