Which term describes the modification of a message during transmission without detection?

The term that describes the modification of a message during transmission without detection is known as a Man-in-the-Middle (MITM) attack. In this scenario, an attacker positions themselves between two parties communicating over a network. The attacker can capture and potentially alter the messages exchanged between these parties without their knowledge, enabling them to intercept sensitive information or inject malicious data.

In this context, MITM attacks are particularly insidious because they often go undetected. The sender and receiver are tricked into believing they are communicating directly with each other, while in reality, the attacker is manipulating the content of their communication. This highlights the importance of securing communications through encryption and authentication, which can help mitigate the risks associated with such attacks.

Other terms, although related to security, have distinct meanings. Interception refers to the act of capturing data in transit, which does not necessarily imply modification. Alteration implies changing data but does not inherently involve the method of communication or the stealth aspect associated with MITM. Injection typically describes the act of inserting malicious code or data into a program or transmission, which is a different attack vector altogether.