It was unattended in a hotel room at the time:

Israel’s Mossad espionage agency used Trojan Horse programs to gather intelligence about a nuclear facility in Syria the Israel Defense Forces destroyed in 2007, the German magazine Der Spiegel reported Monday.

According to the magazine, Mossad agents in London planted the malware on the computer of a Syrian official who was staying in the British capital; he was at a hotel in the upscale neighborhood of Kensington at the time.

The program copied the details of Syria’s illicit nuclear program and sent them directly to the Mossad agents’ computers, the report said.