The chairman of logistics giant Toll Group has revealed the crippling cyber attack that hit it at the end of January came from Russian-based hackers, describing it as a terrible lesson for the company, and a warning for other organisations that they were not safe.

Toll chairman John Mullen, who is also the chairman of Telstra, went further than the company's managing director Thomas Knudsen, who this week told The Australian Financial Review that he did not know where its attackers were based, and gave dramatic insight into the tough decision about whether to pay the hackers' ransom.