Report: NSA investigating attack on NASDAQ

The National Security Agency has joined the investigation of an October cyber attack on the owners of the NASDAQ stock exchange, according to a report from Bloomberg.

According to the report, NSA joined the investigation after evidence showed the breach was more severe than initially disclosed. The investigation, parts of which are classified, is lead by the FBI and involves foreign intelligence agencies.

NSA's involvement demonstrates the severity of the attack, which could potentially undermine confidence in the nation's second-largest stock exchange. The motive remains unclear but experts said the severity suggested a state-sponsored or similarly sophisticated attack.

House Financial Services chairman Spencer Bachus (R-Ala.) told Bloomberg the attack prompted a review of the security of the nation's financial infrastructure starting last month.

NSA is considered the federal agency with the most expertise with regards to cybersecurity. It is lead by Gen. Keith Alexander, who also commands the military's Cyber Command unit. The intelligence agency has been increasingly involved in defending the nation's networks and investigating major breaches.

The security of the nation's financial infrastructure has been a topic central to the ongoing cybersecurity debate, particularly within the Senate. Several bills introduced last year would likely designate stock exchanges and other financial institutions as critical infrastructure crucial to the nation's economic security.

As such, their security practices could potentially be subject to any new cybersecurity standards mandated by legislation such as the bill unveiled by the Senate Homeland Security Committee.

Republicans have in the past shown a preference for allowing intelligence agencies such as NSA and the military safeguard the nation's critical infrastructure. President George W. Bush signed an executive order in 2008 that tasked NSA with detecting cyber attacks against federal networks.