Hours after anti-Israel hackers said they would strike the websites of the Tel Aviv
Stock Exchange and El Al, both sites were taken offline overnight on Monday.
The
Tel Aviv Stock Exchange website made a swift recovery and was back
online by Monday morning, but the El Al website remained unavailable
into the morning.
RELATED:Hackers post 1000s of Israeli credit card numbers 'Saudi hacker disseminates third harmful file' The prominent hacker 0xOmar, who has been at the
forefront of an Internet assault on Israel, and who released tens of thousands
of Israeli credit card numbers last month, sent an email to
The Jerusalem Post
before the attack.
He said he had been joined by a hacking team called
"Nightmare." The new group "promised to take down" the two websites by morning,
he added.
El Al released a statement saying it was aware that "a cyber
war has been waged against the State of Israel for two weeks. El Al is closely
monitoring the activities of the Saudi hacker [0xOmar]." El Al said steps being
taken to fortify its official website "could cause disruptions to the website's
activities." Both websites supply key information to members of the public, and
their attack represents an escalation in the web war being waged against
Israel.

The
Tel Aviv Stock Exchange confirmed it was targeted and said it was
subject to a denial of service attack (DoS), in which a server is
flooded with hits, making it unavailable to other users.
TASE said its technicians were working to ensure its website would be fully operational on Monday. It stressed that computers that handle trading were unaffected.
In denial of service attacks, hackers often plant Trojan horses in large
numbers of computers, then 'hijack' the computers and order them to
send requests to the targeted server, thereby inundating it.
Israeli hackers have
said in recent days that they will launch
their own attacks against Arab hackers in the event of future hacking incidents
against Israelis.
Meanwhile, a Jewish pro-Israel hacker named
Hannibal published information enabling web users to break into the
accounts of 20,000 Arab Facebook users.
Hannibal said he held
information that would allow for the breaking in to 10 million Iranian
and Saudi bank accounts, and threatened to cause billions of dollars
worth of damages.
Hamas on Sunday also called for an escalation of Internet hacking against Israel,
saluting Arab programmers who have managed to infiltrate Israeli
computer systems.
“Penetrating Israeli websites means opening a new field of resistance
and the beginning of an electronic war against Israeli occupation,”
Hamas spokesman Sami Abu Zuhri said in a statement e-mailed to reporters
in the Gaza Strip.
Nadav Shemer contributed to this report.