Shoulder surfing is passive, like eavesdropping and traffic analysis.
Masquerading is the only one where you are actually doing something by changing something -
actively doing something.

The major functional groups of protocols and methods are the Application Layer, the Transport Layer, the Internet Layer, and the Link Layer (RFC 1122). It should be noted that this model was not intended to be a rigid reference model into which new protocols have to fit in order to be accepted as a standard.
The following table provides some examples of the protocols grouped in their respective layers.

Firewalls tend to give a false sense of security. They can be very hard to bypass but they need to be properly configured. The complexity of configuration rules can introduce a vulnerability when the person responsible for its configuration does not fully understand all possible options and switches. Denial of service attacks mainly concerns availability.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-
Hill/Osborne, 2002, Chapter 3: Telecommunications and Network Security (page 412).

Unauthorized access of restricted network services by the circumvention of security access controls is known as logon abuse. This type of abuse refers to users who may be internal to the network but access resources they would not normally be allowed.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the
Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3:
Telecommunications and Network Security (page 74).