Hackers were able to deliver malware to the more one million-plus Asus computer owners last year by hijacking the vendor’s software update system, security researchers have revealed.
Moscow-based cyber security provider Kaspersky Lab said the attack took place between June and November last year and was used to deliver a software update with a "backdoor" that would give hackers access to infected machines.
"We are not able to calculate the total count of affected users based only on our data; however, we estimate that the real scale of the problem is much bigger and is possibly affecting over a million users worldwide," Kaspersky said in a blog post.
"The cyber criminals behind it were not interested in all of them, however - they targeted only 600 specific MAC addresses, for which the hashes were hardcoded into different versions of the utility.
"While investigating this attack, we found out that the same techniques were used against software from three other vendors. Of course, we have notified ASUS and other companies about the attack."
Researchers at cyber security specialist Symantec were also able to identify the attack against Asus users, a Symantec spokeswoman said.
"Symantec telemetry shows that at least 13,000 computers received the Trojanised updates," a Symantec blog added. "80 per cent of victims were consumers and 20 per cent were from organisations. Our telemetry shows an even spread of victims across the globe."
Asus said it would provide a statement on Tuesday.
The attack, which was first reported by technology news website Motherboard, shows how hackers are able to leverage the size of technology companies and their suppliers to reach large numbers of victims.
Kaspersky said that more than 57,000 of its users had downloaded and installed the compromised Asus update but the hackers intended to target a smaller number of unknown victims.
Kaspersky said it informed Asus about the attack in January and was assisting the company with its investigation.
(Reporting by Vibhuti Sharma in Bengaluru, Angela Moon in New York and Jack Stubbs in London; Editing by James Emmanuel and David Goodman)