Ben-Gurion University researchers have developed a new attack scenario, dubbed aIR-Jumper, which includes an infected air-gapped computer (from which data needs to be stolen) and an infected CCTV network (that has at least one CCTV installed inside the premises facing the infected computer and one outside the premises), assuming that both networks are isolated from each other, and none of them is Internet-connected. Attackers can simply capture the blink of the CCTV using their own camera and can decrypt the data later.
Source: https://thehackernews.com/2017/09/airgap-network-malware-hacking.html