exfiltrate

The Optus fiasco has brought this item, a jargon word originally from the US military, into the open.  If ever there was a word that was crying out to have an opposite it was infiltrate and yet, since its use in the 1700s for the physical process of causing a fluid to permeate through pores, it did not have one.  But in the 1980s the US army created exfiltration to mean the surreptitious removal of troops from an area into which they had been infiltrated. The verb to exfiltrate was a backformation from that.

Exfiltration was picked up by the IT world.  Instead of troops being secretly removed from an area, it was data being quietly withdrawn.  And so there was mention of data from Optus having been exfiltrated.  No one has yet referred to the exfiltrator but it would be logical to do so.