New Kimsuky Malware "EndClient RAT": Technical Report and IOCs
Source AlienVault OTX General
Description
EndClient RAT is a newly identified Remote Access Trojan attributed to the North Korean Kimsuky group, targeting human rights defenders. Delivered via a signed Microsoft Installer package disguised as 'StressClear.msi', it uses AutoIT scripts for execution and establishes persistence through scheduled tasks and startup folder entries. The malware communicates with its command and control server using a custom protocol with JSON markers, enabling remote shell access, file upload/download, and system reconnaissance. It employs in-memory modules for binary search, Base64 encoding/decoding, and LZMA decompression to evade detection. Detection rates are currently low, increasing the risk of undetected compromise. While primarily targeting North Korean human rights defenders, the malware's capabilities pose risks to any organization with similar exposure or interest. No known exploits in the wild have been reported yet, but the threat is medium severity due to its stealth and persistence mechanisms.