A pro-Palestinian hacking group disrupted the website of the Israeli-developed mobile messaging application WhatsApp with anti-Israel messages.
A computer virus attacked thousands of Israeli Facebook subscribers days before a threatened mass cyber attack on Israeli websites.
Israeli officials said on Friday they were concerned the country may be under cyber attack after a wave of credit card code thefts in the past week by a hacker who claims to be operating out of Saudi Arabia.
Israeli government and military websites were back on-line a day after an apparent cyber attack.
Several Israeli government websites crashed on Sunday in what appeared to be a cyber-attack by hackers. The websites of the IDF, Mossad and the Shin Bet security services were among the sites that went down, as well as several government portals and ministries.