In your explanation, provide an example of a case where prescriptive jurisdiction exists, but enforcement jurisdiction is absent.

Assume that citizen X of country A instigates a cyber-attack that closes down defense facilities in country B.  The attack is launched from a base in country A.  On what basis could country B purport to exercise jurisdiction over citizen X in order to bring her to justice?   What assistance, if any, is country A obliged to provide under international law?  You may refer to any widely-ratified UN treaties that you consider relevant.