The MSI installer for Splashtop Streamer for Windows before 3.6.2.0 uses a temporary folder with weak permissions during installation. A local user can exploit this to escalate privileges to SYSTEM by replacing InstRegExp.reg.
The product uses weak credentials (such as a default key or hard-coded password) that can be calculated, derived, reused, or guessed by an attacker.
By design, authentication protocols try to ensure that attackers must perform brute force attacks if they do not know the credentials such as a key or password. However, when these credentials are easily predictable or even fixed (as with default or hard-coded passwords and keys), then the attacker can defeat the mechanism without relying on brute force. Credentials may be weak for different reasons, such as:
Even if a new, unique credential is intended to be generated for each product installation, if the generation is predictable, then that may also simplify guessing attacks.