Spy agencies 'ban Lenovo from secret networks' The ban is only thought to apply to the most highly restricted networks, and Lenovo remains a significant supplier of computers for "unclassified" government networks in these countries. In a statement, Lenovo said it has not received word of any sort of a restriction of sales, claiming that its products "have been found time and time again to be reliable and secure by our enterprise and public sector customers," adding that it welcomes their engagement to ensure it is meeting their security needs. The Home Office refused to either confirm or deny that Lenovo products are accredited for the UK's secret networks. Meanwhile, a GCHQ spokesman said that it does not routinely discuss the names or nature of suppliers. Lenovo is currently the biggest PC supplier in the world, according to the latest numbers from IDC and Gartner. The company's global market share reached 16.7 per cent in the second quarter of 2013, up from 15 per cent in the same period last year. However, there is widespread suspicion in the West that even non-state owned businesses in China have close ties with the government through the ubiquitous Communist Party committees which operate within them, and allegedly cast "a shadow source of power and influence" (in the words of a recent US Congressional report). Last week, former NSA and CIA chief Michael Hayden claimed in an interview with AFR to have seen 'hard evidence' of backdoors in Chinese firm Huawei's networking equipment, describing the company as an "unambiguous national security threat." The company denied the existence of any such back doors. "Supply chain security is a significant concern for governments and the critical infrastructure community," said Tom Kellermann, VP of cybercrime at security company Trend Micro, commenting on the news. There have been rumours that there are hardware-based rootkits in some of these products. A hardware-based rootkit/backdoor is literally indefensible.