DUBAI ⁠— An attack that knocked out half of Saudi Arabia's oil production capacity has cast a shadow over state-owned oil giant Aramco and its long-awaited initial public offering, poised to be the largest in history.

Saudi Aramco CEO Amin Nasser told the media just last week that the mammoth company would list on the Riyadh stock exchange "very soon" as bankers from J.P. Morgan, Goldman Sachs, Credit Suisse and Citigroup met in Dubai to kick-start work on the gigantic offering.

News of the weekend attack sent money streaming into safe haven assets Monday morning, and industry experts questioned the security of Aramco's assets and the confidence of its future shareholders.

"Saturday's attacks raise the fear of future attacks in a very real way for equities investors," Ellen Wald, president of Transversal Consulting and author of the book "Saudi, Inc." told CNBC via email Sunday.

"Those familiar with the company know that Aramco has been prepared for this for a very long time, but it likely is not something already priced into the opinions of the typical fund."

Riyadh has not offered a timeline for the recovery of all of Aramco's production capacity, a central factor to the direction of oil prices. Sources close to the firm say it could take anywhere from days or weeks to months. The strikes, which have been claimed by Yemen's Houthi rebels, but which some U.S. officials blame on Iran, took out roughly 5.7 million barrels per day of Saudi oil production — equivalent to 5% of global daily crude output.