Viral protein involved in the evasion of host innate defense by inhibiting the interferon signaling pathway leading to the production of interferon-induced genes. Interferons bind to the IFN receptors (IFNAR) on the cell surface and activate Jak/Tyk kinases. These kinases phosphorylate STAT1 and STAT2 that translocate to the nucleus and induce the expression of interferon stimulated genes (ISGs). Many viruses interact with components of this pathway to prevent expression of ISGs and inhibit the host immune response.