CVE-2011-2705

La función SecureRandom.random_bytes de lib/securerandom.rb de Ruby en versiones anteriores a 1.8.7-p352 y 1.9.x anteriores a 1.9.2-p290 se basa en valores PID para la inicialización, lo que facilita a atacantes dependientes del contexto predecir la cadena resultado utilizando el conocimiento de cadenas aleatorias obtenidas en procesos anteriores con el mismo PID.

Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to do system management tasks. It was found that Ruby did not reinitialize the PRNG after forking a child process. This could eventually lead to the PRNG returning the same result twice. An attacker keeping track of the values returned by one child process could use this flaw to predict the values the PRNG would return in other child processes. A flaw was found in the Ruby SecureRandom module. When using the SecureRandom.random_bytes class, the PRNG state was not modified after forking a child process. This could eventually lead to SecureRandom.random_bytes returning the same string more than once. An attacker keeping track of the strings returned by one child process could use this flaw to predict the strings SecureRandom.random_bytes would return in other child processes.