Newly SLEEPWALKER Backdoor Waits for One Crafted Packet, Then Runs Its Own Bytecode

A previously unreported Windows backdoor, dubbed SLEEPWALKER, has been identified by a malware researcher. The backdoor remains dormant until a specific crafted network packet is received, at which point it executes a custom bytecode language to monitor network interfaces and potentially facilitate lateral movement. It impersonates Microsoft's dpapi.dll and relies on side-loading into ESET Management Agent, requiring local administrator privileges to install. The analysis reveals a complex architecture with multiple transport mechanisms and a focus on stealth, making detection challenging. The backdoor is a post-compromise implant, and its initial infection vector remains unknown.