The chemical reactions and pathways performed by a virus resulting in the hydrolysis of the host MAVS (mitochondrial inhibitor of viral signaling) protein by cleavage of peptide bonds, thereby inhibiting the host innate immune response. For example, MAVS harbors a C-terminal transmembrane domain that targets it to the mitochondrial outer membrane; cleavage within this domain removes MAVS from the membrane, thus preventing it from signaling.