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Business email compromise scammers operating out of Nigeria have been targeting government healthcare agencies, COVID-19 research organizations, and pandemic response organizations to obtain fraudulent wire transfer payments and spread malware.
The attacks were detected by Palo Alto Networks’ Unit 42 team researchers and have been attributed to a cybercriminal organization called SilverTerrier. SilverTerrier actors have been highly active over the past 12 months and are known to have conducted at least 2.1 million BEC attacks since the Unit 42 team started tracking their activity in 2014. In 2019, the group conducted an average of 92,739 attacks per month, with activity peaking in June when 245,637 attacks were conducted.
The gang has been observed exploiting the CVE-2017-11882 vulnerability in Microsoft Office to install malware, but most commonly uses spear phishing emails targeting individuals in the finance department. The gang uses standard phishing lures such as fake invoices and payment advice notifications to trick recipients into opening malicious email attachments that install malware. A wide range of malware variants have been used by the gang, including information stealers such as Lokibot, Pony, and PredatorPain and remote administration tools to maintain persistent access to compromised systems. The gangs use malware to steal sensitive information and gain access to bank accounts and payroll systems. BEC attacks are also conducted to obtain fraudulent wire transfer payments.
Unit 42 researchers have tracked the activity of three threat actors from the group over the past 3 months who, between them, have conducted 10 COVID-19 themed malware campaigns on organizations involved in the national response to COVID-19 in Australia, Canada, Italy, the United Kingdom, and the United States.
Recent targets have included government healthcare agencies, local and regional governments, medical publishing companies, research firms, insurance companies, and universities with medical programs and medical centers. 170 distinct phishing emails have been identified by the researchers, several of which related to supplies of face masks and other personal protective equipment.
SilverTerrier attacks increased by 172% in 2019 and Palo Alto Networks reports there is no indication that the attacks will slow in 2020. “In light of this trend, we encourage government agencies, healthcare and insurance organisations, public utilities, and universities with medical programs to apply extra scrutiny to Covid-19-related emails containing attachments,” said the researchers. Since the attacks are mostly conducted by email, the best defense is training for staff to help them identify spear phishing emails and an advanced spam filtering solution to prevent the emails from being delivered to inboxes. It is also important to check to make sure that the CVE-2017-11882 Microsoft Office vulnerability and to continue to apply patches promptly.