An attacker uses a network sniffer to capture the packets of a transaction that adds $20 to a gift card. The attacker then user a function of the sniffer to push those packets back onto the network…

An integer overflow attack occurs when a program attempts to store a numeric value larger than the data type allocated to it, leading to incorrect calculations or memory corruption, which is not what is depicted here.

A Smurf attack is a type of Distributed Denial of Service (DDoS) attack that uses ICMP echo requests with a spoofed source IP to flood a target, not related to retransmitting transaction data.

A replay attack involves an attacker intercepting a valid data transmission, capturing the communication, and then illicitly retransmitting it to produce an unauthorized or duplicate effect. In this case, the attacker replays the packets that initially added $20 to the gift card, causing the transaction to execute multiple times due to the re-submission of the valid packet sequence.

A buffer overflow attack involves writing more data to a buffer than it can hold, overwriting adjacent memory and potentially executing malicious code, which is different from replaying network traffic.

A cross-site scripting (XSS) attack involves injecting malicious client-side scripts into web pages to be executed by other users, primarily targeting web application vulnerabilities rather than network packet retransmission.