The world’s biggest personal computer maker has reportedly been banned from supplying equipment for intelligence and defense services of Australia, the United States, Britain, Canada and New Zealand. The ban was introduced in the mid-2000s after intensive laboratory testing of its equipment. The US State Department decided not to use 16,000 new Lenovo computers on classified networks because of security concerns. Backdoor vulnerabilities in hardware and firmware were apparently discovered during the tests which could allow attackers to remotely access devices without the knowledge of the owner.
Source: https://thehackernews.com/2013/07/Lenovo-banned-Intelligence-Chinese-backdoor-vulnerabilities.html