[BreachExchange] FBI: OnePercent Group Ransomware targeted US orgs since Nov 2020

[Sophia Kingsbury]

https://www.bleepingcomputer.com/news/security/fbi-onepercent-group-ransomware-targeted-us-orgs-since-nov-2020/

The Federal Bureau of Investigation (FBI) has shared info about a threat
actor known as OnePercent Group that has been actively targeting US
organizations since at least November 2020 as a ransomware affiliate.

The US federal law enforcement agency shared indicators of compromise,
tactics, techniques, and procedures (TTP), and mitigation measures in a
flash alert published on Monday.

"The FBI has learned of a cyber-criminal group who self identifies as the
'OnePercent Group' and who have used Cobalt Strike to perpetuate ransomware
attacks against US companies since November 2020," the FBI said.

"OnePercent Group actors encrypt the data and exfiltrate it from the
victims’ systems. The actors contact the victims via telephone and email,
threatening to release the stolen data through The Onion Router (TOR)
network and clearnet, unless a ransom is paid in virtual currency."

Victims' networks breached via phishing

The threat actors use malicious phishing email attachments that drop IcedID
banking trojan payload on targets' systems. After infecting them with the
trojan, the attackers download and install Cobalt Strike on compromised
endpoints for lateral movement throughout the victims' networks.

After maintaining access to their victims' networks for up to one month and
exfiltrating files before deploying the ransomware payloads, OnePercent
will encrypt files using a random eight-character extension (e.g., dZCqciA)
and will add uniquely named ransom notes linking to the gang's .onion
website.

Victims can use the Tor website to get more info on the demanded ransom,
negotiate with the attackers, and get "technical support.'

Victims will be asked to pay the ransom in bitcoins in most cases, with a
decryption key provided up to 48 hours after the payment is made.

According to the FBI, the ransomware affiliate will also reach out to their
victims using spoofed phone numbers, threatening to leak the stolen data
unless they're connected with a company negotiator.

"Once the ransomware is successfully deployed, the victim will start to
receive phone calls through spoofed phone numbers with ransom demands and
are provided a ProtonMail email address for further communication," the FBI
added.

"The actors will persistently demand to speak with a victim company’s
designated negotiator or otherwise threaten to publish the stolen data.

Applications and services used by the OnePercent Group operators include
AWS S3 cloud, IcedID, Cobalt Strike, Powershell, Rclone, Mimikatz,
SharpKatz, BetterSafetyKatz, SharpSploit.

REvil ransomware affiliate with Maze and Egregor links

While the FBI hasn't provided any information on OnePercent Group's past
attacks, the agency linked the ransomware affiliate to the notorius REvil
(Sodinokibi) ransomware gang, whose data leak site they've used to leak and
auction their victims' stolen files.

"If the ransom is not paid in full after the "one percent leak," OnePercent
Group actors threaten to sell the stolen data to the Sodinokibi Group  to
publish at an auction," the FBI said.

Command-and-control servers mentioned in FBI's IOC list (golddisco[.]top
and june85[.]cyou) also point to the UNC2198 threat actor known for using
ICEDID to deploy Maze and Egregor ransomware.

The same IOCs were also mentioned in a Team Cymru report from May 2021 on
mapping active IcedID network infrastructure.
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