North Korean cyber actors have developed a Remote Access Trojan (RAT) called "EndClient RAT," targeting human rights defenders in South Korea and internationally. This malware evades antivirus detection by using stolen code-signing certificates and is delivered through a Microsoft Installer package named "StressClear.msi," which is signed by a Chinese firm. The RAT deploys an AutoIT-based payload, creates a scheduled task for persistence, and communicates with its command-and-control server using a custom protocol. Detection rates for EndClient RAT are low, with only 7 out of 64 detections for the dropper and 1 out of 64 for the payload script. Organizations are advised to block identified indicators of compromise and treat signed MSIs as untrusted until verified.