PictShare before version 3.7.1 contains a weak randomness vulnerability where the getRandomString() function uses the non-cryptographic rand() PRNG to generate the delete_code authorization token in src/inc/core.php. Attackers can predict or infer the PRNG state to guess valid delete_code values and perform unauthorized deletion of hosted files without needing to read the code from the info endpoint.
Weakness
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG’s algorithm is not cryptographically strong.
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.