Anonymous group claims responsibility for attack on HSBC website. Bank says it is working hard to restore service. Some sites are now back up and running. RBS, Lloyds TSB and Barclays are next, FawkesSecurity says. It is also possible that HSBC was targeted by the Izz ad-Din al-Qassam Cyber Fighters as part of a campaign to get the controversial Innocence of Muslims video removed from YouTube removed from the controversial video on the site of the video.
Source: https://thehackernews.com/2012/10/hsbc-hit-by-anonymous-denial-of-service.html