Final answer:
The most likely answer is keylogger, which is a type of malware that captures keystrokes on a compromised device.
Step-by-step explanation:
The most likely answer is keylogger. A keylogger is a type of malware that captures keystrokes on a compromised device, including text that is typed. This would explain the large amounts of text found in the packet capture data. With a keylogger installed, an attacker can secretly record everything the user types, including passwords and sensitive information.