Threat Group Cards: A Threat Actor Encyclopedia Archived: 2026-04-06 00:42:39 UTC Home > List all groups > List all tools > List all groups using tool BigpipeLoader Tool: BigpipeLoader Names BigpipeLoader Category Malware Type Loader Description (Trend Micro) Since this loader will read/write encrypted payload through a named pipe, we named this shellcode loader BigpipeLoader. In one of our threat hunting sessions, we found two variants of this loader with different execution procedures. The first variant of BigpipeLoader just drops the decoy file and loads the Cobalt Strike payload into the memory, then proceeds to execute it. In the second variant, however, the attacker creates a dropper, which drops the malicious WTSAPI32.dll designed to be sideloaded by a legitimate application with the file name “wusa.exe”. This launches the encrypted BigpipeLoader (chrome.inf). Both variants of BigpipeLoader use the AES-128-CFB algorithm to decrypt the payload. Information Last change to this tool card: 19 November 2022 Download this tool card in JSON format All groups using tool BigpipeLoader Changed Name Country Observed APT groups       ↳ Subgroup: Earth Longzhi 2020-Apr 2023   1 group listed (1 APT, 0 other, 0 unknown) https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=bf77aa3f-d900-4311-91f0-47f5d8c9a6e1 Page 1 of 2 Source: https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=bf77aa3f-d900-4311-91f0-47f5d8c9a6e1 https://apt.etda.or.th/cgi-bin/listgroups.cgi?u=bf77aa3f-d900-4311-91f0-47f5d8c9a6e1 Page 2 of 2 APT groups ↳ Subgroup: Earth Longzhi 2020-Apr 2023 1 group listed (1 APT, 0 other, 0 unknown) Page 1 of 2