John visits an online shop that stores the IDs and prices of the items to buy in a cookie. After selecting the items that he wants to buy, the attacker changes the price of the item to 1. Original…

Cookie poisoning occurs when an attacker edits cookie data stored in their browser to override values that the server trusts without independent validation. Here, John directly modifies the ItemPrice fields in his cookie before clicking Buy, causing the server to calculate a fraudulently low total based on the attacker-controlled values rather than the legitimate prices.

Cross-site scripting injects malicious client-side scripts into pages viewed by other users and does not involve directly editing cookie key-value pairs to manipulate transaction logic.

A man-in-the-middle attack requires intercepting communication between two parties in transit - John is modifying his own local cookie directly, not eavesdropping on a network channel.

Computer-based social engineering deceives users into divulging information or performing actions through manipulation, not through direct alteration of stored data values.