An authentication flaw exists in the password-recovery functionality of TP-Link RE305 V3. The verification-code interface allows an unauthenticated attacker on the same local network to trigger generation of an administrator password-reset verification code. Because the interface lacks an effective attempt counter or lockout mechanism and uses a predictable verification-code generation process, an attacker may obtain or brute-force the code and reset the administrator password.
Successful exploitation may allow an unauthenticated attacker on the local network to reset the administrator password and subsequently access privileged device-management functions.
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.