The Login Lockdown & Protection plugin for WordPress is vulnerable to IP Block Bypass in all versions up to, and including, 2.14. This is due to $unblock_key key being insufficiently random allowing unauthenticated users, with access to an administrative user email, to generate valid unblock keys for their IP Address. This makes it possible for unauthenticated attackers to bypass blocks due to invalid login attempts.
Weakness
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
Potential Mitigations
- Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.
- In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.
- Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a “random enough” number.
References