C0057 3CX Supply Chain Attack

The 3CX Supply Chain Attack was the first publicly reported case of one supply chain compromise triggering another, leading to a cascading, two-stage intrusion. The initial supply chain attack began when a 3CX employee downloaded and executed a trojanized, end-of-life version of the X_Trader trading software from Trading Technologies. This provided UNC4736, a threat cluster associated with AppleJeus, access to the 3CX environment. From there UNC4736 compromised the Windows and macOS build environments used to distribute the 3CX desktop application to their customers. While 3CX serves more than 600,000 customers and 12 million users, only a subset of systems were affected. Subsequent targeting focused on victims in the defense and cryptocurrency sectors, where attackers deployed secondary payloads such as Gopuram for credential theft and persistence. The campaign began in late 2022 and was disrupted after security vendors publicly reported the compromise in March 2023.