The CBI on Saturday registered a case against unknown persons for hacking and defacement of its official website by people who identified themselves as "Pakistani Cyber Army".
The CBI registered the case under various sections of Information Technology Act and said efforts were underway to restore the website for public interface at the earliest, an official spokesperson said in New Delhi.
In a brief statement, the spokesperson said, "It has come to the notice of the CBI that its official website was unauthorisedly accessed and defaced in the intervening night of December 3 and 4.
"A case has been registered in this connection in the cyber crime cell of the CBI and efforts are underway to restore the website with the help of National Informatics Centre and the CBI cyber security experts," the spokesperson said.
The home page of the CBI website was hacked and it had a message from the 'Pakistani Cyber Army' warning the 'Indian Cyber Army' that their websites should not be attacked.
The hackers infiltrated into the CBI website, supposed to be one of the most secure websites. The CBI is connected to the command centre of world police organisation - Interpol - 24x7.
The message from the hackers also spoke about the filtering controls provided by the NIC, a body which mans computer servers across the country.
Intelligence agencies have been often warning the government that proper cyber security was not being ensured in offices and that no security audit was being carried out.
The 'Pakistani Cyber Army' also threatened to carry out "mass defacement" of other websites.