A security device may receive, from a client device, a request associated with a server device. The security device may determine a communication channel and contact information for validating the request. The security device may provide validation information via the communication channel using the contact information. The security device may receive a validation response from the client device, and may determine whether the validation response is valid. The security device may selectively perform a first action or a second action based on determining whether the validation response is valid. The first action may be performed based on determining that the validation response is valid, and may include providing a validation indicator, with the request, to the server device. The second action may be performed based on determining that the validation response is not valid, and may include providing an invalidation indicator, with the request, to the server device.