What characterizes a replay attack?

• A. An attempt to steal data from a system
• B. Replaying an authorized request to duplicate its effects
• C. A method to prevent unauthorized access
• D. An update to system security measures

Answer: (B)

A replay attack is specifically characterized by the act of capturing and re-sending a previously authorized request to achieve the same effect as the original request. In this type of attack, the attacker intercepts valid data sent over a network—often authentication messages or transaction requests—and then retransmits that data without authorization. This action exploits the fact that the request is legitimate and may lead to unauthorized activities, such as unauthorized fund transfers or repeated access to restricted resources.

The process of replaying a request enables the attacker to benefit from the original user's permissions and privileges, effectively circumventing security measures aimed at providing access control. This form of attack highlights vulnerabilities in systems that do not incorporate measures to validate requests and distinguish between original and repeated transactions.