During the course of an intrusion investigation in late October 2023, Mandiant observed novel N-day exploitation of CVE-2023-46747 affecting F5 BIG-IP Traffic Management User Interface. Additionally, in February 2024, we observed exploitation of Connectwise ScreenConnect CVE-2024-1709 by the same actor. This mix of custom tooling and the SUPERSHELL framework leveraged in these incidents is assessed with moderate confidence to be unique to a People's Republic of China (PRC) threat actor, UNC5174.
Mandiant assesses UNC5174 (believed to use the persona "Uteus") is a former member of Chinese hacktivist collectives that has since shown indications of acting as a contractor for China's Ministry of State Security (MSS) focused on executing access operations. UNC5174 has been observed attempting to sell access to U.S. defense contractor appliances, UK government entities, and institutions in Asia in late 2023 following CVE-2023-46747 exploitation. In February 2024, UNC5174 was observed exploiting ConnectWise ScreenConnect vulnerability (CVE-2024-1709) to compromise hundreds of institutions primarily in the U.S. and Canada....read more!
