The group has planned street protests in 16 cities later in the evening. In Delhi, the protests will be held at Jantar Mantar.
"This is your response team #india! They can't even protect themselves. How will they protect others," read a tweet from @opindia_revenge, the group's twitter handle. "We will keep attacking http://cert-in.org.in and http://india.gov.in ! #GOI, ready to face ups and downs?" the hackers said.
This is the latest in a series of high-profile attacks on government and corporate websites made by the group in the last one month. The India-wing of Anonymous, a collective of internet activists, had downed websites of Internet Service Providers Association of India, All-India Trinamool Congress and Reliance Communications on charges of internet censorship.
It brought down the official website of Mahanagar Telephone Nigam Limited (MTNL) through the distributed denial of service (DDoS) attack on Wednesday. In the CERT-In attack too, the group has used DDoS that prevents users from accessing the site.
DDoS attack is different from hacking. It overwhelms the servers on which a website, in this case CERT-In, is hosted. For how long the website would remain inaccessible depends on the response from CERT-In engineers and the intensity of the attack by Anonymous. The group on its Twitter feed has said that it is aiming to keep CERT- In website down for the whole day but it may not be possible. The Anonymous India is aided by Anonymous UK that tweeted: "#TangoDown http://cert-in.org.in #OpIndia want it down all day xD."
Anonymous started attacking official websites to protest web censorship after internet service providers (ISPs) like Airtel, Reliance Communications, on May 17 in India blocked several video sharing and file sharing websites such as Vimeo, Dailymotion.com, thepiratebay.org, torrentz.eu, on the basis of an order against web piracy by a Madras High Court. Though the order did not explicitly demand blocking of websites, the ISPs played safe. Anonymous has been arguing that instead of removing pirated links on websites, the Indian ISPs blocked entire sites that contained material hosted by other users and thus violated the right to freedom of expression.
Since then, Anonymous called for protests in real world, asking people to speak out against web censorship and the IT rules that were framed last year.
The planned protests are in some ways modeled on the Occupy Wall Street, which was supported by Anonymous. The group has gathered support for its cause on the web using Twitter and Facebook to reach out to people and asking them to organize protests in their respective cities. It has asked protesters to wear the Guy Fawkes mask, which was made famous by HollywoodFilm V For Vendetta and in the recent years has been adopted by Anonymous as its symbol.
A hacker who goes by the name of Isaac and who is allegedly a part of Anonymous said on Twitter, "Today we tell them we will not we oppressed, Today we will let them know we will not be silenced, Today we Protest!"
Last night the group said on twitter that protests have to be peaceful. "#india --> Tomorrow we stand for our rights. We stand to free internet. To #stopCensorship. Do not be afraid. Keep calm. No violence," it tweeted.
Also in a message at PasteHTML.com, the group said "Anonymous is completely apolitical collective of free thinkers". It said that if any politician wants to join the protests he can do so "as a common man fighting for free internet, fighting for free speech"