New Delhi: Former Union home secretary G.K. Pillai alleged on Wednesday that when he was in charge, some subordinates used to watch pornographic content on the Internet in their North Block office and ended up downloading malware, posing a threat to computer network security.

Malware is a software that is specifically designed to disrupt, damage, or gain authorised access to a computer system.

The revelation came days after 10 government websites, including those of the home and defence ministries, became inaccessible to the public.

Initial reports on Friday had suggested that the websites had been hacked, but the government later clarified that there was no cyber attack and blamed it on a glitch.

"When I was Union home secretary almost eight-nine years ago, every 60 days we would find the entire computers compromised," Pillai said while addressing a financial security conclave in Mumbai.

Presently, he chairs the non-profit Data Security Council of India promoted by Nasscom. Pillai had served as home secretary when P. Chidambaram was Union home minister during the UPA II regime. He retired in June 2011.

Pillai said that while senior officials remained busy with meetings, the subordinates had a lot of free time while they waited for post-meeting work. "So what will they (the subordinates) do? They go and open the Internet and they are on porn sites and so on and so forth, and download all sorts of things that come up with all the malware."

He said the ministry issued a lot of directives and a detailed review led to the discovery.

On Friday, 10 government websites, including those of the defence, home and labour ministries, the departments of public enterprises and science and technology, the Election Commission and the EPFO, hosted by the National Informatics Centre data centre became inaccessible to the public.

Within minutes, defence minister Nirmala Sitharaman had tweeted that the website had been hacked after what seemed to be a Chinese character appeared on the homepage.

The ministry immediately asked the NIC to probe the suspected hacking.

At night the NIC explained that the character that appeared on the website was the "default logo" of Drupal, a content-management software.