so at one given point of time, that middle box had access to plaintext as well? It may not be accessible plaintext when the middlebox is at resting state, but

so at one given point of time, that middle box had access to plaintext as well? It may not be accessible plaintext when the middlebox is at resting state, but it certainly has access to plaintext at its active state. Given enough time, such Middlebox too may succumb to a malicious payload whose active but plaintext memory region gets targeted and exploited by.