There is firmware in the MagSafe cable. I just recently did an update. So it may be technically possible. I also think the NBC News article was sprinkled with a lot of sensationalism. The UEFI boot BIOS was thought to be very secure. Yet is has been compromised on some MSI motherboards.
No, it isn't technically possible.
MagSafe does not transmit data. It has no ability to do so. It relies on NFC.