Multiple classes used within Apereo CAS before release 6.1.0-RC5 makes use of apache commons-lang3 RandomStringUtils for token and ID generation which makes them predictable due to RandomStringUtils PRNGs algorithm not being cryptographically strong.
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG’s algorithm is not cryptographically strong.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Central_authentication_service | Apereo | * | 6.0.5.1 (including) |
| Central_authentication_service | Apereo | 6.1.0-rc1 (including) | 6.1.0-rc1 (including) |
| Central_authentication_service | Apereo | 6.1.0-rc2 (including) | 6.1.0-rc2 (including) |
| Central_authentication_service | Apereo | 6.1.0-rc3 (including) | 6.1.0-rc3 (including) |
| Central_authentication_service | Apereo | 6.1.0-rc4 (including) | 6.1.0-rc4 (including) |
When a non-cryptographic PRNG is used in a cryptographic context, it can expose the cryptography to certain types of attacks. Often a pseudo-random number generator (PRNG) is not designed for cryptography. Sometimes a mediocre source of randomness is sufficient or preferable for algorithms that use random numbers. Weak generators generally take less processing power and/or do not use the precious, finite, entropy sources on a system. While such PRNGs might have very useful features, these same features could be used to break the cryptography.