Security Market Segment LS
Tuesday, 22 October 2019 09:41

Attacker gets into Avast network, apparently targets CCleaner again


Security firm Avast has revealed that its internal network was breached through the use of a compromised VPN profile, with the target being CCleaner, a popular application that allows Windows users to perform routine maintenance on their systems and has been downloaded more than two billion times.

The company made the admission in a blog post on Monday, with spokesperson Jaya Baloo saying that suspicious activity had been noticed on 23 September and an investigation launched thereafter. It was found that the attacker in question had been inside the network since 14 May.

Avast's CCleaner was used to spread malware by a malicious attacker two years ago, with researchers from Cisco's Talos Intelligence Group noticing this and informing Avast about it.

"The evidence we gathered pointed to activity on MS ATA/VPN [Microsoft Advanced Threat Analytics] on 1 October, when we re-reviewed an MS ATA alert of a malicious replication of directory services from an internal IP that belonged to our VPN address range, which had originally been dismissed as a false positive," Baloo wrote.

"The user, whose credentials were apparently compromised and associated with the IP, did not have domain admin privileges. However, through a successful privilege escalation, the actor managed to obtain domain admin privileges. The connection was made from a public IP hosted out of the UK and we determined the attacker also used other endpoints through the same VPN provider."

Baloo said after further analysis, it was found that the internal network had been successfully accessed with compromised credentials through a temporary VPN profile that had erroneously been kept enabled and did not require 2FA.

She said the company had then halted upcoming CCleaner releases and checked prior updates to see it any malware had been infiltrated into the popular software.

The compromised VPN account was left open for a while to see if there would be any further attempts at infiltration but as soon as the new versions of CCleaner were ready for release, the account was shut down, Baloo said.

"We do not know if this was the same actor as before and it is likely we will never know for sure, so we have named this attempt 'Abiss'," she wrote.


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Sam Varghese

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Sam Varghese has been writing for iTWire since 2006, a year after the site came into existence. For nearly a decade thereafter, he wrote mostly about free and open source software, based on his own use of this genre of software. Since May 2016, he has been writing across many areas of technology. He has been a journalist for nearly 40 years in India (Indian Express and Deccan Herald), the UAE (Khaleej Times) and Australia (Daily Commercial News (now defunct) and The Age). His personal blog is titled Irregular Expression.



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