A new threat actor that appears to be financially motivated has targeted many organizations in the United States and other countries using several new pieces of malware, FireEye reported on Tuesday.
The threat actor, which does not appear to be linked to other known groups, is tracked by the cybersecurity firm as UNC2529 (UNC stands for uncategorized). The phishing campaign conducted by UNC2529 targeted a wide range of organizations, and involved the use of a sizable command and control (C&C) infrastructure, three sophisticated malware families, and custom lures.
FireEye, whose incident response unit Mandiant observed two attack waves in December 2020, described the group as “experienced and well resourced.” The company spotted 28 targeted organizations in the first wave and believes there were at least 22 in the second wave.
Roughly 70% of victims were spotted by FireEye in the United States, including organizations in the financial, business services, health, retail, military and aerospace, engineering and manufacturing, government, education, transportation, and utilities sectors.
The cybercriminals also targeted organizations in the EMEA region, Asia and Australia. However, FireEye has admitted there is some “telemetry bias” considering that it has more customers in the U.S. compared to other countries.
“Although Mandiant has no evidence about the objectives of this threat actor, their broad targeting across industries and geographies is consistent with a targeting calculus most commonly seen among financially motivated groups,” FireEye said.
The attacks launched by UNC2529 start with a phishing email containing a link to a malicious or compromised website that serves a piece of malware. The emails had subject lines that were tailored to the targeted organization.
The attacks involved three previously unseen pieces of malware tracked by FireEye as DOUBLEDRAG, DOUBLEDROP and DOUBLEBACK. DOUBLEDRAG is a downloader delivered in the first stage of the attack and which in some cases was replaced with a malicious Excel document that served as a downloader.
DOUBLEDRAG is designed to connect to a C&C server and fetch DOUBLEDROP, a memory-only dropper that deploys DOUBLEBACK, a backdoor that is apparently still under development.
“The threat actor made extensive use of obfuscation and fileless malware to complicate detection to deliver a well coded and extensible backdoor,” FireEye said. “UNC2529 is assessed as capable, professional and well resourced. The identified wide-ranging targets, across geography and industry suggests a financial crime motive.”