Insecure Client Nonce Generation in Authen::DigestMD5 for Perl

CVE-2025-40919

What is CVE-2025-40919?

Authen::DigestMD5 for Perl vulnerabilities arise from the insecure generation of client nonce (cnonce) values in versions 0.01 and 0.02. It employs an MD5 hash constructed from the process ID (PID), the current epoch time, and the built-in rand function. This methodology is flawed as the PID originates from a limited set of values, and the epoch time can often be anticipated, especially if shared in HTTP headers. Furthermore, the rand function lacks cryptographic security, making the nonce susceptible to attacks that could compromise user authentication and data integrity. According to RFC 2831, a secure cnonce should contain a minimum of 64 bits of entropy, which this implementation does not achieve.

References