Which attack method involves a legitimate request being sent more than once to forge actions?

• A. Replay Attack
• B. Denial of Service
• C. Masquerade Attack
• D. Modification of Messages

Answer: (A)

A replay attack is a method where an attacker captures and re-sends valid data transmission to trick a system into executing that transaction again. This technique exploits the legitimate nature of the original request to manipulate the target system into performing unauthorized actions based on previously sent messages. For example, if a user sends a valid request to transfer funds, an attacker intercepting that request can resend it to initiate a duplicate transaction without the user's consent.

This attack method is particularly effective in environments where request validation lacks proper timestamping or session identifiers that could distinguish between new and old requests. By replaying the legitimate request, the attacker effectively forges actions that appear to be valid and authorized, thereby compromising the integrity and confidentiality of the communication.

In contrast, denial of service attacks aim to overwhelm systems with traffic, masquerade attacks involve impersonating a legitimate user, and modification of messages pertains to altering the data in transit. These methods do not focus on the repetition of legitimate requests in the way that replay attacks do.