China-based Lenovo Group, a leading personal computer maker, had pre-installed a virus-like software on laptops that made the devices more vulnerable to hacking, according to a report.

Experts said the program called ‘Superfish’ on Lenovo’s consumer laptops was ‘adware’ or software that automatically displayed adverts, reported the Arab News.

Superfish was malicious software that hijacks and throws open encrypted connections, paving the way for hackers to also commandeer these connections and eavesdrop, in what is known as a man-in-the-middle attack,  Robert Graham, chief executive of US-based security research firm Errata Security, was quoted as saying.

An administrator on Lenovo's official web forum recently said that Superfish has been temporarily removed from consumer computers, according to the report.

Lenovo executives were not immediately available for comment during the Lunar New Year holiday in China.

Graham and other experts said Lenovo was negligent, and that computers could still be vulnerable even after uninstalling Superfish, it said.

The software throws open encryptions by giving itself authority to take over connections and declare them as trusted and secure, even when they are not, it added.