Officials Report No Cyberattack Behind Nationwide FAA Outage

US officials say there is no evidence that hackers caused a nationwide Federal Aviation Administration (FAA) ground stop on Friday, November 13, after a communications failure hit air route traffic control centres. The outage halted flight departures across the United States for more than four hours, disrupting thousands of flights before lifting at 8:15 pm ET. Although departures have resumed, officials expect delays to persist for several days. The FBI, CISA, the NSA, and the Department of Defense are assisting an investigation examining whether a software update on the L3Harris-operated communications network overwhelmed legacy routing equipment.

Key Facts

Was the FAA Outage Caused by a Cyberattack?

US officials have found no evidence that hackers or criminal activity caused the November 13 FAA ground stop. While agencies including the FBI, NSA, Department of Defense, and CISA continue investigating, officials say the failure appears mechanical rather than the result of a cyberattack.

Homeland Security Secretary Markwayne Mullin told reporters at the White House that investigators had not observed attack indicators, though they had not closed the door entirely while inquiries proceed.

"There’s no chatter, we haven’t seen any footprints. However, we’re still looking, so we’re not going to rule that out."

Markwayne Mullin, US Homeland Security Secretary

Bloomberg separately reported, citing a person familiar with the matter, that the FBI does not believe a cyberattack or criminal activity was behind the outage.

Multiple US agencies, including the FBI and CISA, are investigating the FAA outage and have found no indicators of a cyberattack so far.

What Triggered the Communications Network Failure?

No official root cause has been announced, though investigators are examining whether a software update overwhelmed older FAA network hardware. Transportation Secretary Sean Duffy said network switches and routers were flooded with data and produced inconsistent information, prompting the agency to shut the system down as a precaution.

Mullin pointed to ongoing maintenance as a possible trigger, saying it appeared the FAA had been applying patches and installing new equipment and technology, which "was overwhelming the older system." Citing multiple sources, CBS News reported that the outage followed an update to the private communications network operated by L3Harris that links the air traffic control system, causing the network to reboot and crash. Officials added that the incident was unrelated to the Microsoft outage earlier in the week and that the FAA’s recently deployed AI systems played no role.

Investigators are examining a software update on the L3Harris-operated communications network and legacy hardware overload, while ruling out links to the earlier Microsoft outage and FAA AI systems.

How Serious Was the Disruption and Has This Happened Before?

The November 13 ground stop halted flight departures nationwide for more than four hours before the order was lifted at 8:15 pm ET. The outage disrupted thousands of flights, and although departures have resumed, officials expect delays to continue for several days.

The incident marks the first nationwide FAA ground stop since January 2023. In that previous disruption, a contractor unintentionally deleted files while working on the system that delivers safety notices to pilots, and investigators similarly found no evidence of a cyberattack.

The outage halted US departures for over four hours, disrupted thousands of flights, and echoed a January 2023 non-cyber ground stop caused by accidental file deletion.

What Should You Do?

• Note that no fix is available yet: US officials have not announced an official root cause or software fix, and no cyberattack indicators have been identified that require third-party emergency containment.
• Stage updates carefully on legacy networks: IT administrators managing older switches and routers should plan and monitor patches and new equipment rollouts carefully, given officials’ concerns that patching and upgrades may have overwhelmed legacy FAA hardware.
• Monitor US travel schedules: Travellers and organisations with connecting flights or cargo moving through US airports should expect lingering delays for several days following the November 13 disruption.
• Report suspected cyber incidents in Malaysia: Organisations or users who spot unrelated suspicious network activity can report cyber incidents to Cyber999 (MyCERT) or contact the National Scam Response Centre at 997 for scams.

Common Questions

Did the earlier Microsoft outage or FAA AI systems cause the ground stop?

No. US officials stated that the FAA communications outage had nothing to do with the Microsoft outage earlier in the week. Officials also confirmed that the agency's recently deployed AI systems played no role in the disruption.

Which agencies are investigating the FAA communications outage?

According to Homeland Security Secretary Markwayne Mullin, the NSA, the Department of Defense, CISA, and other agencies have been involved in investigating the incident. Bloomberg also reported that the FBI is looking into a software update as a potential cause.

When did US flight departures resume after the ground stop?

The FAA lifted its nationwide ground stop at 8:15 pm ET on Friday, November 13, more than four hours after issuing the order. Although flight departures have resumed, officials expect delays affecting thousands of disrupted flights to continue for several days.

Sources and Methodology

This dispatch is based solely on the SecurityWeek report by Eduard Kovacs, No Signs of Hacking in FAA Ground Stop as FBI Reportedly Probes Software Update, which cites public remarks from US officials alongside reporting from Bloomberg and CBS News. No other documents, advisories, or vendor pages were reviewed.