The major imminent investments in quantum technologies will bring concepts like a global quantum Internet and quantum Internet-of-Things, closer to reality. Our findings reveal a new form of vulnerability that will enable hostile groups of quantum-enabled adversaries to inflict maximal disruption on the global quantum state in such systems. These attacks will be practically impossible to detect since they introduce no change in the Hamiltonian and no loss of purity; they require no real-time communication; and they can be over within a second. We also predict that such attacks will be amplified by the statistical character of modern extremist, insurgent and terrorist groups. A countermeasure could be to embed future quantum technologies within redundant classical networks.