“Unconfirmed reports suggest that HSBC was targeted by the Izz ad-Din al-Qassam Cyber Fighters as part of a current campaign (see Pastebin post*) to get the controversial Innocence of Muslims video removed from YouTube. The group also took credit for interrupting customer access to the websites of Capital One earlier this week, again without warning, WSJ reports. The same group staged a series of digital sit-in (denial of service) attacks against US banks including Bank of America and Chase last month.”
Source:HSBC websites fell in DDoS attack last night, bank admits • The Register