Lenovo, the world’s biggest personal computer maker; which is based in Beijing has been blacklisted by multiple spy agencies for having 'back-door' hardware and vulnerable firmware.

According to the article in The Verge, British intelligence agency research found "back-door" hardware and vulnerable firmware in Lenovo products, leading them to warn that the company could pose a security threat in light of its ties to the Chinese government.

Lenovo, which acquired IBM's PC wing in 2005, was apparently unaware of the alleged ban. "We have not received word of any sort of a restriction of sales," it told The Independent, saying it was "looking into this situation closely." Australia's Department of Defence told AFR that Lenovo computers hadn't been approved for secret or top-secret networks, but Britain's GCHQ declined to comment. However, this isn't the first time we've heard about trouble with security agencies. In 2006, the US State Department said that 16,000 Lenovo computers would not be used on classified systems, making sure they would not "compromise our information and communication channels." These latest reports suggest that the decision was consistent with a larger international policy, which covered the CIA, the UK's MI5 and MI6, and other agencies.

The Financial Review notes that the classified ban highlights concerns about security threats posed by “malicious circuits” and insecure firmware in chips produced in China by companies with close government ties. Firmware is the interface be­tween a computer’s hardware and its operating system.

What's not clear is whether Lenovo actually includes any of the alleged "backdoors," or whether its security vulnerabilities are meant to let prying eyes look into top-secret networks.