The key to stopping the next ISIS attack could be to go after the group's money, a top Treasury official said Wednesday.
"When two terrorists talk on cell phones, they'll use code, they probably won't use each other's real names, and they are going to make lots of efforts to mask what they're doing," Adam Szubin, the Treasury's acting undersecretary for terrorism and financial intelligence, said at briefing Wednesday.
"If you're sending money to somebody, you're going to have to use their real name, you're going to have to use identifiers, whether it is an address, a telephone number," he said. "And so that's the sense in which I mean it's very rich data and it's there for us."
And then, it's about connecting the dots — tracking down those individuals.
Related: How ISIS Funds Its Terrorism Network
Following the money could also help officials decide which oil refineries to target with airstrikes. The United States is already working to target the group's entire oil supply chain, because it's a top source of revenue. "From the oil fields and wellheads, to the refineries and processing plants, to the tanker trucks themselves," Szubin said.
Thursday, for the first time, a summit of finance ministers will take place at the U.N. Security Council to discuss how to combat ISIS financing. The meeting will be led by U.S. Treasury Secretary Jacob Lew. Ministers are expected to approve a resolution, co-sponsored by the United States and Russia, that would focus an existing al Qaeda sanctions regime on ISIS.
"This has the opportunity to be more than a photo-op," said Matthew Levitt, director of the Stein Program on Counterterrorism and Intelligence at the Washington Institute for Near East Policy.
"Any time you can get high-level attention to this and give a shot in the arm ... it's something that's not insignificant," Levitt said.
The resolution, which is expected to pass, would also make associating with ISIS a sanctionable offense and call for more information sharing between countries and private sector companies, like banks.
Szubin said cooperation with banks is an integral part of tracking down ISIS financing
"It's about when banks see a suspicious transaction, are they flagging that for financial authorities, and if they are and that system is working well, is that information then accessible to law enforcement, and can it be married with travel data, can it be married with intelligence data, so that we can have the best possible chance of disrupting the next attack?"
While al Qaeda gets most of its funds from outside donors, ISIS is different because it generates most of its money from taxation and extortion of people inside the territory it controls, as well as oil and gas sales. Together, they generate hundreds of millions of dollars.
Estimates for oil and gas sales alone are about $400 million per year. And even though that's a huge amount of revenue, officials see an opening, because ISIS also spends a huge amount of money. It's incredibly costly to fight a war, try to establish a caliphate, pay foreign fighters and govern its territory.
"None of that is cheap," Szubin said. "Our strategy is to put a major dent into that. ... And you will see, when foreign fighters can't be paid ... it has an impact on the battlefield. It has an impact on morale. And it has an impact on what the group can do."
Much of what the government has recently learned about ISIS financing has come from a daring raid on senior ISIS leader Abu Sayyaf's home. In May, U.S. special forces unintentionally killed the ISIS financier known as the "emir" of ISIS oil and gas operations.
The White House is also hoping to draw attention to Szubin's stalled confirmation. He was nominated to his post on April 20. Republicans have blocked confirmation of many appointments, including those of judges, ambassadors and others, which are unlikely to come before the end of the year.