Technical glitches that temporarily grounded United Airlines planes and halted trading on the New York Stock Exchange on Wednesday look to be "system malfunctions" rather than "the result of any nefarious actor," Homeland Security Director Jeh Johnson said.

Johnson said less is known about another anomaly that made the Wall Street Journal's website inaccessible, although Johnson noted that the Journal's website is "back up."

Johnson said he reached his conclusion that United's problem was not a malicious hacking incident after personally speaking to the airline's CEO. The NYSE confirmed that its issue was an internal malfunction in a statement before Johnson started a pre-scheduled speech on cybersecurity at the Center for Strategic and International Studies.

"We're currently experiencing a technical issue that we're working to resolve as quickly as possible," NYSE stated. "We will be providing further updates as soon as we can, and are doing our utmost to produce a swift resolution, communicate thoroughly and transparently, and ensure a timely and orderly market re-open."

As part of his prepared remarks, Johnson said hacks such as those against the Office of Personnel Management "demonstrate the urgency for acting now."