Crypt::PasswdMD5 versions through 1.42 for Perl generates insecure random values for salts.
The built-in rand function is predictable, and unsuitable for cryptography.
Weakness
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG’s algorithm is not cryptographically strong.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libcrypt-passwdmd5-perl | Ubuntu | esm-apps/xenial | * |
| Libcrypt-passwdmd5-perl | Ubuntu | questing | * |
Extended Description
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.
Potential Mitigations
References
- https://github.com/ronsavage/Crypt-PasswdMD5/commit/a2f821637db0296082297aa4b02254ab08f0dc5e.patch
- https://github.com/ronsavage/Crypt-PasswdMD5/pull/3
- https://metacpan.org/release/RSAVAGE/Crypt-PasswdMD5-1.42/source/lib/Crypt/PasswdMD5.pm#L35-47
- https://metacpan.org/release/RSAVAGE/Crypt-PasswdMD5-1.43/changes
- http://www.openwall.com/lists/oss-security/2026/05/08/17