In May, the Dow Jones Industrial Average plummeted 1,000 points in less than half an hour after a trading algorithm malfunctioned, exposing the vulnerabilities of stock exchanges that increasingly rely on digital infrastructure. This weekend we got another reminder when the Nasdaq OMX Group, which runs the Nasdaq stock exchange, revealed that hackers broke into a service for corporate officers to share confidential documents.

Investigators are trying to determine whether the attack was an act of terrorism or an effort to obtain trade secrets or illegal trading advantages, the Wall Street Journal reports. The hackers planted malware files inside Nasdaq's Directors Desk web application but didn't acquire private information or breach Nasdaq's trading platform, which accounts for around 19 percent of U.S. stock trading. While some evidence suggests the hackers were from Russia, they may have simply been using Russian computers.

What are the implications for Nasdaq and the financial world?

• Attack on Trading Could Be Devastating, states Larry Dignan at ZDNet: "If hackers did eventually get to electronic trading systems--algorithms rule the stock market roost these days--they could spark a crash that would make last May's 'flash crash' look like a day at the beach."
  

• As Could Attacks Beyond Stock Market, adds Dean Takahashi at VentureBeat: "If hackers can penetrate Nasdaq, maybe they can break into the computer systems of other secure entities, from air traffic control systems to defense computers."

• Is the Status Quo Sustainable? wonders Alex Salkever at DailyFinance: "The case is shaking some bedrock assumptions of a digitized, high-speed, globally connected stock market run essentially by computers with minimal human interaction ... [and] could cause a decrease of confidence that stock exchanges can safeguard the interests of investors large and small." He wonders whether it would be possible for hackers to add "a small amount to each offer or bid for a specific group of securities" and capture "the differential over millions of trades in a manner that could go undetected for long periods."

• Cyber Attacks Are Rising, observes Business Insider's Pascal-Emmanuel Gobry, "especially on financial systems and companies, for obvious reasons (money!)." He points to recent reports that the London Stock Exchange struggled with hackers last year when it switched to an open source-based trading system.
  

• Nasdaq's Trading Service Is Secure, notes Christopher Drew at The New York Times. While the Nasdaq breach may spark concern about cyber attacks on banks and stock exchanges, Drew explains, trading platforms generally boast sophisticated protections against hackers. Nasdaq's more pressing concern is reassuring customers about the security of its non-trading services like Directors Desk, he says.
  

Want to add to this story? Let us know in comments or send an email to the author at ufriedman at theatlantic dot com. You can share ideas for stories on the Open Wire.
Uri Friedman