In the context of network security, a spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining an illegitimate advantage.
Spoofing and TCP/IP
Many of the protocols in the TCP/IP suite do not provide mechanisms for authenticating the source or destination of a message. They are thus vulnerable to spoofing attacks when extra precautions are not taken by applications to verify the identity of the sending or receiving host. IP spoofing and ARP spoofing in particular may be used to leverage man-in-the-middle attacks against hosts on a computer network. Spoofing attacks which take advantage of TCP/IP suite protocols may be mitigated with the use of firewalls capable of deep packet inspection or by taking measures to verify the identity of the sender or recipient of a message.
Referrer spoofing
Some websites, especially pornographic paysites, allow access to their materials only from certain approved (login-) pages. This is enforced by checking the referrer header of the HTTP request. This referrer header however can be changed (known as "referrer spoofing" or "Ref-tar spoofing"), allowing users to gain unauthorized access to the materials.
Poisoning of file-sharing networks
"Spoofing" can also refer to copyright holders placing distorted or unlistenable versions of works on file-sharing networks.
Caller ID spoofing
Public telephone networks often provide Caller ID information, which includes the caller's name and number, with each call. However, some technologies (especially in Voice over IP (VoIP) networks) allow callers to forge Caller ID information and present false names and numbers. Gateways between networks that allow such spoofing and other public networks then forward that false information. Since spoofed calls can originate from other countries, the laws in the receiver's country may not apply to the caller. This limit's laws' effectiveness against the use of spoofed Caller ID information to further a scam.
E-mail address spoofing
The sender information shown in e-mails (the "From" field) can be spoofed easily. This technique is commonly used by spammers to hide the origin of their e-mails and leads to problems such as misdirected bounces (i.e. e-mail spam backscatter).
E-mail address spoofing is done in quite the same way as writing a forged return address using snail mail. As long as the letter fits the protocol, (i.e. stamp, postal code) the SMTP protocol will send the message. It can be done using a mail server with telnet.
GPS Spoofing
A GPS spoofing attack attempts to deceive a GPS receiver by broadcasting a slightly more powerful signal than that received from the GPS satellites, structured to resemble a set of normal GPS signals. These spoofed signals, however, are modified in such a way as to cause the receiver to determine its position to be somewhere other than where it actually is, specifically somewhere determined by the attacker. Because GPS systems work by measuring the time it takes for a signal to travel from the satellite to the receiver, a successful spoofing requires that the attacker know precisely where the target is so that the spoofed signal can be structured with the proper signal delays. A GPS spoofing attack begins by broadcasting a slightly more powerful signal that produces the correct position, and then slowly deviates away towards the position desired by the spoofer, because moving too quickly will cause the receiver to lose signal lock altogether, at which point the spoofer works only as a jammer. It has been suggested that the capture of a Lockheed RQ-170 drone aircraft in northeastern Iran in December, 2011, was the result of such an attack. GPS spoofing attacks had been predicted and discussed in the GPS community previously, but no known example of a malicious spoofing attack has yet been confirmed.A "proof-of-concept" attack was successfully performed in June, 2013, when the luxury yacht "White Rose" was misdirected with spoofed GPS signals from Monaco to the island of Rhodes by a group of mechanical engineering students from the Cockrell School of Engineering at the University of Texas in Austin. The students were aboard the yacht, allowing their spoofing equipment to gradually overpower the signal strengths of the actual GPS constellation satellites, altering the course of the yacht.
