(Reuters) – Western intelligence agencies are investigating a cyberattack by unidentified hackers that disrupted broadband satellite internet access in Ukraine coinciding with Russia’s invasion, according to three people with direct knowledge of the incident.
Analysts for the US National Security Agency, French government cybersecurity organization ANSSI, and Ukrainian intelligence are assessing whether the remote sabotage of a satellite internet provider’s service was the work of Russian-state backed hackers preparing the battlefield by attempting to sever communications.
The digital blitz on the satellite service began on Feb. 24 between 5 a.m. and 9 a.m., just as Russian forces started going in and firing missiles, striking major Ukrainian cities including the capital, Kyiv.
The consequences are still being investigated but satellite modems belonging to tens of thousands of customers in Europe were knocked offline, according to an official of US telecommunications firm Viasat, which owns the affected network.
The hackers disabled modems that communicate with Viasat Inc’s KA-SAT satellite, which supplies internet access to some customers in Europe, including Ukraine. More than two weeks later some remain offline, resellers told Reuters.
What appears to be one of the most significant wartime cyberattacks publicly disclosed so far has piqued the interest of Western intelligence because Viasat acts as a defense contractor for both the United States and multiple allies.
Government contracts reviewed by Reuters show that KA-SAT has provided internet connectivity to Ukrainian military and police units.
Pablo Breuer, a former technologist for US special operations command, or SOCOM, said knocking out satellite internet connectivity could handicap Ukraine’s ability to combat Russian forces.
“Traditional land-based radios only reach so far. If you’re using modern smart systems, smart weapons, trying to do combined arms maneuvers, then you must rely on these satellites,” said Breuer.
The Russian Embassy in Washington did not immediately return a message seeking comment. Moscow has repeatedly rejected allegations that it participates in cyberattacks.
Russian soldiers have besieged Ukrainian cities in what the Kremlin describes as a “de-Nazification” operation that has been denounced by the West as an unprovoked assault and led to severe sanctions against Moscow as punishment.
Viasat said in a statement that the disruption for customers in Ukraine and elsewhere was triggered by a “deliberate, isolated and external cyber event” but has yet to provide a detailed, public explanation of what happened.
“The network is stabilized and we are restoring service and activating terminals as quickly as possible,” spokesperson Chris Phillips said in an email, adding that the company was prioritizing “critical infrastructure and humanitarian assistance.”
The affected modems appeared to be completely inoperative, according to Jaroslav Stritecky, who runs Czech telecommunications company INTV. Normally, he said, the four status lights on the curved, SurfBeam 2 modems would indicate whether they were connected to the internet. After the attack, the lights on the Viasat-made devices would not turn on at all.
The Viasat official said a misconfiguration in the “management section” of the satellite network had allowed the hackers remote access into the modems, knocking them offline. He said most of the affected devices would need to be reprogrammed either by a technician on site or at a repair depot and that some would have to be swapped out.
The Viasat official wasn’t explicit about what the “management section” of the network referred to and declined to provide further details. KA-SAT and its associated ground stations, which Viasat purchased last year from European company Eutelsat, are still operated by a Eutelsat subsidiary.
Eutelsat referred questions back to Viasat.
Viasat has hired US cybersecurity firm Mandiant, which specializes in tracking state-sponsored hackers, to investigate the intrusion, according to two people familiar with the matter.
Spokespeople for the NSA, ANSSI, and Mandiant declined to comment.
Viasat said government clients who procured services directly from the company were unaffected by the disruption. The KA-SAT network is operated, however, by a third party, which in turn farms out service through various distributors.
Over the past several years Ukraine’s military and security services have purchased several different communications systems that run over Viasat’s network, according to contracts posted on ProZorro, a Ukrainian transparency platform.
A message seeking comment from the Ukrainian military was not immediately returned.
Some internet distributors are still waiting to replace their devices.
Stritecky, the Czech telecom executive, said he did not blame Viasat.
He recalled coming into work on the morning of the invasion and seeing a monitor showing regional satellite coverage in the Czech Republic, neighboring Slovakia, and Ukraine all in red.
“It was immediately clear what happened,” he said.
(Reporting by James Pearson, Raphael Satter, Christopher Bing and Joel Schectman; Editing by Chris Sanders and Grant McCool)