Phishing is a technique of fraudulently obtaining private information. Typically, the phisher sends an e-mail that appears to come from a legitimate business—a bank or credit card company—requesting "verification" of information and warning of some dire consequence if it is not provided. The e-mail usually contains a link to a fraudulent web page that seems legitimate—with company logos and content—and has a form requesting everything from a home address to an ATM card's PIN.
For example, 2003 saw the proliferation of a phishing scam in which users received e-mails supposedly from eBay claiming that the user's account was about to be suspended unless a link provided was clicked to update a credit card (information that the genuine eBay already had). Because it is relatively simple to make a Web site resemble a legitimate organization's site by mimicking the HTML code, the scam counted on people being tricked into thinking they were being contacted by eBay and subsequently, were going to eBay's site to update their account information. By spamming large groups of people, the "phisher" counted on the e-mail being read by a percentage of people who already had listed credit card numbers with eBay legitimately, who might respond.
Phone phishing (or "vishing") uses a rogue interactive voice response (IVR) system to recreate a legitimate-sounding copy of a bank or other institution's IVR system. The victim is prompted (typically via a phishing e-mail) to call the "bank" via a (ideally toll free) number provided in order to "verify" information. A typical system will reject log-ins continually, ensuring the victim enters PINs or passwords multiple times, often disclosing several different passwords. More advanced systems transfer the victim to the attacker posing as a customer service agent for further questioning.
Baiting is like the real-world Trojan Horse that uses physical media and relies on the curiosity or greed of the victim.
In this attack, the attacker leaves a malware infected floppy disk, CD-ROM, or USB flash drive in a location sure to be found (bathroom, elevator, sidewalk, parking lot), gives it a legitimate looking and curiosity-piquing label, and simply waits for the victim to use the device.
For example, an attacker might create a disk featuring a corporate logo, readily available from the target's web site, and write "Executive Salary Summary Q2 2012" on the front. The attacker would then leave the disk on the floor of an elevator or somewhere in the lobby of the targeted company. An unknowing employee might find it and subsequently insert the disk into a computer to satisfy their curiosity or a good samaritan might find it and turn it in to the company.
In either case, as a consequence of merely inserting the disk into a computer to see the contents, the user would unknowingly install malware on it, likely giving an attacker unfettered access to the victim's PC and, perhaps, the targeted company's internal computer network.
Unless computer controls block the infection, PCs set to "auto-run" inserted media may be compromised as soon as a rogue disk is inserted.
Hostile devices, more attractive than simple memory, can also be used. For instance, a "lucky winner" is sent a free digital audio player that actually compromises any computer it is plugged to.
Quid pro quo
Quid pro quo means something for something:
An attacker calls random numbers at a company claiming to be calling back from technical support. Eventually this person will hit someone with a legitimate problem, grateful that someone is calling back to help them. The attacker will "help" solve the problem and, in the process, have the user type commands that give the attacker access or launch malware.
In a 2003 information security survey, 90% of office workers gave researchers what they claimed was their password in answer to a survey question in exchange for a cheap pen. Similar surveys in later years obtained similar results using chocolates and other cheap lures although they made no attempt to validate the passwords.
An attacker, seeking entry to a restricted area secured by unattended, electronic access control, e.g. by RFID card, simply walks in behind a person who has legitimate access. Following common courtesy, the legitimate person will usually hold the door open for the attacker or the attackers themselves may ask the employee to hold it open for them. The legitimate person may fail to ask for identification for any of several reasons or may accept an assertion that the attacker has forgotten or lost the appropriate identity token. The attacker may also fake the action of presenting an identity token.