Security researchers discovered a sophisticated and previously undocumented backdoor, named Deadglyph, used by the Stealth Falcon group for espionage in the Middle East.
Stealth Falcon, which is a nation-state threat actor active since at least 2012, targeted political activists and journalists in the Middle East in past campaigns.
The name Deadglyph comes from artifacts found in the backdoor (such as 0xDEADB001) and the presence of a homoglyph attack.
The Deadglyph’s architecture is composed of cooperating components, a native x64 binary and other .NET assembly.
The ESET researchers explained that unlike other malware typically using components written in only one programming language, Deadglyph uses distinct programming languages. The authors used different languages to hinder analysis.
Deadglyph dynamically received the commands from the C2 in the form of additional modules. The malware also supports multiple evasion capabilities.
The researchers analyzed a successful attack on a governmental entity in the Middle East, but they also discovered on VirusTotal a sample of the same malware that was uploaded from Qatar.
The researchers have yet to determine the exact method used to deliver the backdoor.
According to the analysis published by ESET, the initial component is a registry shellcode loader, which loads shellcode from the registry. This extracted shellcode loads the native x64 part of the backdoor – the Executor. The Executor subsequently loads the .NET part of the backdoor – the Orchestrator. The only component on system’s disk as a file is the initial component, which is in the form of a Dynamic Link Library (DLL). The remaining components are encrypted and stored within a binary registry value.
The Orchestrator accepts commands from the C2 in the form of tasks, then the malicious code organizes them into three categories: orchestrator tasks, executor tasks, and upload tasks.
Orchestrator tasks are used to manage the configuration of the Network and Timer modules, and also to cancel pending tasks.
Executor tasks are used to manage the backdoor and execute additional modules.
Upload tasks are used to upload the output of commands and errors.
Deadglyph boasts a range of counter-detection mechanisms, including continuous monitoring of system processes and the implementation of randomized network patterns. Furthermore, the backdoor is capable of uninstalling itself to minimize the likelihood of its detection in certain cases.
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