Israeli hackers have claimed credit for downing websites run by the Saudi Stock Exchange (Tadawul) and the Abu Dhabi Securities Exchange (ADX).
The digital operation was apparently conducted in retaliation for the hacking of two prominent Israeli sites on Monday: the Tel Aviv Stock Exchange (TASE) and El Al (Israel Airlines).
The hackers - who called themselves "IDF-Team" - also warned that if attacks against Israeli sites continued, they would "move to the next stage and paralyze websites for a period of two weeks to a month."
As the Israeli daily Ha'aretz notes, another pro-Israel hacker known as "Hannibal" has published a list of 30,000 e-mail addresses and Facebook passwords purportedly belonging to residents residing in a number of Middle Eastern countries.
According to Hannibal, the hack and extract operation kicked off Friday as a "counter-attack" in response to a Saudi hacker who compromised the details of thousands of Israeli credit cards.
"I noticed that poor intelligence of 0x omar and his friends. State of Israel, not to worry, you're in the hands of the world's best hacker that I am. I have about 30 million e-mails of Arabs with passwords I'll post them throughout my life - and my personal list is growing every day [with] hundreds of thousands of emails," Hannibal claimed on Pastebin.
"Also, I received hundreds of emails of senior politicians from France and other countries, who asked me not to publish the list of the 10 million my bank accounts. In addition I also have about 4 million credit cards. Just give a command and I will [leak them]."
It should be noted that various forms of cyber warfare have been waged by civilians in the Middle East for a number of years - and can be traced back to the early days of IRC (Internet Relay Chat) when rival parties battled each other with channel takeovers, scripts, automated bots and flooding attacks.