Caught in their web: Iran reportedly returns fire in US cyberwar

Iran has launched a major cyber counter-offensive on US targets, attacking major Wall Street institutions, Reuters news agency sources report.

Bank of America Corp, JPMorgan Chase and Citigroup have come under ever increasing denial-of-service attacks since the end of last year. The attacks use brute processing force to make a website unavailable to ordinary users, but gain no access to private information.

"Most people didn't take Iran seriously. Now most people are taking them very seriously," a source told Reuters.

Bank of America and JPMorgan Chase experienced unexplained website disruptions earlier this week, and NBC reported that the attacks may have been orchestrated by Iran.