What is SSL primarily used to protect you against?

While SSL's MAC-based integrity checks can detect some session tampering, prevention of session modification is a secondary feature - confidentiality against sniffing is the primary design goal.

SQL injection is a server-side input validation vulnerability that occurs within the application layer; SSL encrypts the transport channel but does nothing to sanitize or validate the data being transmitted.

SSL (Secure Sockets Layer) establishes an encrypted tunnel between client and server using asymmetric key exchange and symmetric encryption for the session, ensuring that even if a third party captures the network traffic they cannot read the plaintext content. This confidentiality protection is the core purpose of SSL and its successor TLS, directly countering passive eavesdropping and packet sniffing attacks. Application-layer threats require separate controls at the application or server level.

Cross-site scripting (XSS) is an application-layer attack involving injection of malicious scripts into web pages viewed by other users, which SSL does not prevent because the malicious content originates from the trusted server itself.