APT_Backdoor_Win_DShell_1

YARA-2025-1032 High general Active

This rule is looking for sections of an integer array which contains the encoded payload along with a selection of Windows functions that are present within a DShell payload

APT_Backdoor_Win_DShell_1.yar Valid Syntax

// Copyright 2020 by FireEye, Inc.
// You may not use this file except in compliance with the license. The license should have been received with this file. You may obtain a copy of the license at:
// https://github.com/fireeye/red_team_tool_countermeasures/blob/master/LICENSE.txt
rule APT_Backdoor_Win_DShell_1
{
    meta:
        description = "This rule is looking for sections of an integer array which contains the encoded payload along with a selection of Windows functions that are present within a DShell payload"
        md5 = "152fc2320790aa16ef9b6126f47c3cca"
        rev = 4
        author = "FireEye"
    strings:
        $e0 = ",0,"
        $e1 = ",1,"
        $e2 = ",2,"
        $e3 = ",3,"
        $e4 = ",4,"
        $e5 = ",5,"
        $e6 = ",6,"
        $e7 = ",7,"
        $e8 = ",8,"
        $e9 = ",9,"
        $e10 = ",10,"
        $e11 = ",11,"
        $e12 = ",12,"
        $e13 = ",13,"
        $e14 = ",14,"
        $e15 = ",15,"
        $e16 = ",16,"
        $e17 = ",17,"
        $e18 = ",18,"
        $e19 = ",19,"
        $e20 = ",20,"
        $e21 = ",21,"
        $e22 = ",22,"
        $e23 = ",23,"
        $e24 = ",24,"
        $e25 = ",25,"
        $e26 = ",26,"
        $e27 = ",27,"
        $e28 = ",28,"
        $e29 = ",29,"
        $e30 = ",30,"
        $e31 = ",31,"
        $e32 = ",32,"
        $e33 = ",33,"
        $e34 = ",34,"
        $e35 = ",35,"
        $e36 = ",36,"
        $e37 = ",37,"
        $e38 = ",38,"
        $e39 = ",39,"
        $e40 = ",40,"
        $e41 = ",41,"
        $e42 = ",42,"
        $e43 = ",43,"
        $e44 = ",44,"
        $e45 = ",45,"
        $e46 = ",46,"
        $e47 = ",47,"
        $e48 = ",48,"
        $e49 = ",49,"
        $e50 = ",50,"
        $e51 = ",51,"
        $e52 = ",52,"
        $e53 = ",53,"
        $e54 = ",54,"
        $e55 = ",55,"
        $e56 = ",56,"
        $e57 = ",57,"
        $e58 = ",58,"
        $e59 = ",59,"
        $e60 = ",60,"
        $e61 = ",61,"
        $e62 = ",62,"
        $e63 = ",63,"
        $e64 = ",64,"
        $s1 = "GetACP"
        $s2 = "GetOEMCP"
        $s3 = "GetCPInfo"
        $s4 = "WriteConsoleA"
        $s5 = "FindFirstFileA"
        $s6 = "FileTimeToDosDateTime"
        $s7 = "FindNextFileA"
        $s8 = "GetStringTypeA"
        $s9 = "GetFileType"
        $s10 = "CreateFileA"
        $s11 = "GlobalAlloc"
        $s12 = "GlobalFree"
        $s13 = "GetTickCount"
        $s14 = "GetProcessHeap"
        $s15 = "UnhandledExceptionFilter"
        $s16 = "ExitProcess"
        $s17 = "GetModuleFileNameA"
        $s18 = "LCMapStringA"
        $s19 = "GetLocalTime"
        $s20 = "CreateThread"
        $s21 = "ExitThread"
        $s22 = "SetConsoleCtrlHandler"
        $s23 = "FreeEnvironmentStringsA"
        $s24 = "GetVersion"
        $s25 = "GetEnvironmentStrings"
        $s26 = "SetHandleCount"
        $s27 = "SetFilePointer"
        $s28 = "DeleteFileA"
        $s29 = "HeapAlloc"
        $s30 = "HeapReAlloc"
        $s31 = "HeapFree"
        $s32 = "GetCommandLineA"
        $s33 = "GetThreadContext"
        $s34 = "SuspendThread"
        $s35 = "FindFirstFileW"
        $s36 = "FindNextFileW"
        $s37 = "FindClose"
        $s38 = "CreateSemaphoreA"
        $s39 = "ReleaseSemaphore"
        $s40 = "ExpandEnvironmentStringsW"
        $s41 = "lstrlenW"
        $s42 = "GetModuleHandleA"
        $s43 = "GetEnvironmentVariableA"
        $s44 = "RtlCaptureContext"
        $s45 = "GlobalMemoryStatus"
        $s46 = "VirtualAlloc"
        $s47 = "Sleep"
        $s48 = "SystemTimeToTzSpecificLocalTime"
        $s49 = "TzSpecificLocalTimeToSystemTime"
        $s50 = "GetTimeZoneInformation"
        $s51 = "TryEnterCriticalSection"
        $s52 = "LoadLibraryA"
        $s53 = "VirtualFree"
        $s54 = "GetExitCodeThread"
        $s55 = "WaitForSingleObject"
        $s56 = "ResumeThread"
        $s57 = "DuplicateHandle"
        $s58 = "GetCurrentProcess"
        $s59 = "GetCurrentThread"
        $s60 = "GetCurrentThreadId"
        $s61 = "InitializeCriticalSection"
        $s62 = "DeleteCriticalSection"
        $s63 = "SwitchToThread"
        $s64 = "LeaveCriticalSection"
        $s65 = "EnterCriticalSection"
        $s66 = "FormatMessageW"
        $s67 = "SetLastError"
        $s68 = "GetEnvironmentVariableW"
        $s69 = "FreeEnvironmentStringsW"
        $s70 = "GetEnvironmentStringsW"
        $s71 = "SetEnvironmentVariableW"
        $s72 = "GetSystemInfo"
        $s73 = "QueryPerformanceFrequency"
        $s74 = "QueryPerformanceCounter"
        $s75 = "CreateProcessW"
        $s76 = "GetStdHandle"
        $s77 = "GetHandleInformation"
        $s78 = "SetHandleInformation"
        $s79 = "WriteFile"
        $s80 = "GetConsoleOutputCP"
        $s81 = "FreeLibrary"
        $s82 = "GetConsoleScreenBufferInfo"
        $s83 = "MultiByteToWideChar"
        $s84 = "RaiseException"
        $s85 = "RtlUnwind"
        $s86 = "GetCurrentDirectoryW"
        $s87 = "IsDebuggerPresent"
        $s88 = "LocalFree"
        $s89 = "WideCharToMultiByte"
        $s90 = "GetCommandLineW"
        $s91 = "ReadFile"
        $s92 = "GetFileSize"
        $s93 = "CloseHandle"
        $s94 = "CreateFileW"
        $s95 = "LoadLibraryW"
        $s96 = "GetProcAddress"
        $s97 = "GetFileAttributesW"
        $s98 = "GetLastError"
        $s99 = "CommandLineToArgvW"
        $s100 = "MessageBoxA"
        $s101 = "RegEnumValueW"
        $s102 = "RegEnumKeyExW"
        $s103 = "RegDeleteValueW"
        $s104 = "RegFlushKey"
        $s105 = "RegQueryInfoKeyW"
        $s106 = "RegDeleteKeyW"
        $s107 = "RegQueryValueExW"
        $s108 = "RegSetValueExW"
        $s109 = "RegOpenKeyW"
        $s110 = "RegOpenKeyExW"
        $s111 = "RegCreateKeyExW"
        $s112 = "RegCloseKey"
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and filesize > 500KB and 105 of ($s*) and $s112 in (3000..4000) and 40 of ($e*)
}

Rule Metadata

description

This rule is looking for sections of an integer array which contains the encoded payload along with a selection of Windows functions that are present within a DShell payload

md5

152fc2320790aa16ef9b6126f47c3cca

author

FireEye

String Definitions

{"name":"$e0","value":"\",0,\""}

{"name":"$e1","value":"\",1,\""}

{"name":"$e2","value":"\",2,\""}

{"name":"$e3","value":"\",3,\""}

{"name":"$e4","value":"\",4,\""}

{"name":"$e5","value":"\",5,\""}

{"name":"$e6","value":"\",6,\""}

{"name":"$e7","value":"\",7,\""}

{"name":"$e8","value":"\",8,\""}

{"name":"$e9","value":"\",9,\""}

{"name":"$e10","value":"\",10,\""}

{"name":"$e11","value":"\",11,\""}

{"name":"$e12","value":"\",12,\""}

{"name":"$e13","value":"\",13,\""}

{"name":"$e14","value":"\",14,\""}

{"name":"$e15","value":"\",15,\""}

{"name":"$e16","value":"\",16,\""}

{"name":"$e17","value":"\",17,\""}

{"name":"$e18","value":"\",18,\""}

{"name":"$e19","value":"\",19,\""}

{"name":"$e20","value":"\",20,\""}

{"name":"$e21","value":"\",21,\""}

{"name":"$e22","value":"\",22,\""}

{"name":"$e23","value":"\",23,\""}

{"name":"$e24","value":"\",24,\""}

{"name":"$e25","value":"\",25,\""}

{"name":"$e26","value":"\",26,\""}

{"name":"$e27","value":"\",27,\""}

{"name":"$e28","value":"\",28,\""}

{"name":"$e29","value":"\",29,\""}

{"name":"$e30","value":"\",30,\""}

{"name":"$e31","value":"\",31,\""}

{"name":"$e32","value":"\",32,\""}

{"name":"$e33","value":"\",33,\""}

{"name":"$e34","value":"\",34,\""}

{"name":"$e35","value":"\",35,\""}

{"name":"$e36","value":"\",36,\""}

{"name":"$e37","value":"\",37,\""}

{"name":"$e38","value":"\",38,\""}

{"name":"$e39","value":"\",39,\""}

{"name":"$e40","value":"\",40,\""}

{"name":"$e41","value":"\",41,\""}

{"name":"$e42","value":"\",42,\""}

{"name":"$e43","value":"\",43,\""}

{"name":"$e44","value":"\",44,\""}

{"name":"$e45","value":"\",45,\""}

{"name":"$e46","value":"\",46,\""}

{"name":"$e47","value":"\",47,\""}

{"name":"$e48","value":"\",48,\""}

{"name":"$e49","value":"\",49,\""}

{"name":"$e50","value":"\",50,\""}

{"name":"$e51","value":"\",51,\""}

{"name":"$e52","value":"\",52,\""}

{"name":"$e53","value":"\",53,\""}

{"name":"$e54","value":"\",54,\""}

{"name":"$e55","value":"\",55,\""}

{"name":"$e56","value":"\",56,\""}

{"name":"$e57","value":"\",57,\""}

{"name":"$e58","value":"\",58,\""}

{"name":"$e59","value":"\",59,\""}

{"name":"$e60","value":"\",60,\""}

{"name":"$e61","value":"\",61,\""}

{"name":"$e62","value":"\",62,\""}

{"name":"$e63","value":"\",63,\""}

{"name":"$e64","value":"\",64,\""}

{"name":"$s1","value":"\"GetACP\""}

{"name":"$s2","value":"\"GetOEMCP\""}

{"name":"$s3","value":"\"GetCPInfo\""}

{"name":"$s4","value":"\"WriteConsoleA\""}

{"name":"$s5","value":"\"FindFirstFileA\""}

{"name":"$s6","value":"\"FileTimeToDosDateTime\""}

{"name":"$s7","value":"\"FindNextFileA\""}

{"name":"$s8","value":"\"GetStringTypeA\""}

{"name":"$s9","value":"\"GetFileType\""}

{"name":"$s10","value":"\"CreateFileA\""}

{"name":"$s11","value":"\"GlobalAlloc\""}

{"name":"$s12","value":"\"GlobalFree\""}

{"name":"$s13","value":"\"GetTickCount\""}

{"name":"$s14","value":"\"GetProcessHeap\""}

{"name":"$s15","value":"\"UnhandledExceptionFilter\""}

{"name":"$s16","value":"\"ExitProcess\""}

{"name":"$s17","value":"\"GetModuleFileNameA\""}

{"name":"$s18","value":"\"LCMapStringA\""}

{"name":"$s19","value":"\"GetLocalTime\""}

{"name":"$s20","value":"\"CreateThread\""}

{"name":"$s21","value":"\"ExitThread\""}

{"name":"$s22","value":"\"SetConsoleCtrlHandler\""}

{"name":"$s23","value":"\"FreeEnvironmentStringsA\""}

{"name":"$s24","value":"\"GetVersion\""}

{"name":"$s25","value":"\"GetEnvironmentStrings\""}

{"name":"$s26","value":"\"SetHandleCount\""}

{"name":"$s27","value":"\"SetFilePointer\""}

{"name":"$s28","value":"\"DeleteFileA\""}

{"name":"$s29","value":"\"HeapAlloc\""}

{"name":"$s30","value":"\"HeapReAlloc\""}

{"name":"$s31","value":"\"HeapFree\""}

{"name":"$s32","value":"\"GetCommandLineA\""}

{"name":"$s33","value":"\"GetThreadContext\""}

{"name":"$s34","value":"\"SuspendThread\""}

{"name":"$s35","value":"\"FindFirstFileW\""}

{"name":"$s36","value":"\"FindNextFileW\""}

{"name":"$s37","value":"\"FindClose\""}

{"name":"$s38","value":"\"CreateSemaphoreA\""}

{"name":"$s39","value":"\"ReleaseSemaphore\""}

{"name":"$s40","value":"\"ExpandEnvironmentStringsW\""}

{"name":"$s41","value":"\"lstrlenW\""}

{"name":"$s42","value":"\"GetModuleHandleA\""}

{"name":"$s43","value":"\"GetEnvironmentVariableA\""}

{"name":"$s44","value":"\"RtlCaptureContext\""}

{"name":"$s45","value":"\"GlobalMemoryStatus\""}

{"name":"$s46","value":"\"VirtualAlloc\""}

{"name":"$s47","value":"\"Sleep\""}

{"name":"$s48","value":"\"SystemTimeToTzSpecificLocalTime\""}

{"name":"$s49","value":"\"TzSpecificLocalTimeToSystemTime\""}

{"name":"$s50","value":"\"GetTimeZoneInformation\""}

{"name":"$s51","value":"\"TryEnterCriticalSection\""}

{"name":"$s52","value":"\"LoadLibraryA\""}

{"name":"$s53","value":"\"VirtualFree\""}

{"name":"$s54","value":"\"GetExitCodeThread\""}

{"name":"$s55","value":"\"WaitForSingleObject\""}

{"name":"$s56","value":"\"ResumeThread\""}

{"name":"$s57","value":"\"DuplicateHandle\""}

{"name":"$s58","value":"\"GetCurrentProcess\""}

{"name":"$s59","value":"\"GetCurrentThread\""}

{"name":"$s60","value":"\"GetCurrentThreadId\""}

{"name":"$s61","value":"\"InitializeCriticalSection\""}

{"name":"$s62","value":"\"DeleteCriticalSection\""}

{"name":"$s63","value":"\"SwitchToThread\""}

{"name":"$s64","value":"\"LeaveCriticalSection\""}

{"name":"$s65","value":"\"EnterCriticalSection\""}

{"name":"$s66","value":"\"FormatMessageW\""}

{"name":"$s67","value":"\"SetLastError\""}

{"name":"$s68","value":"\"GetEnvironmentVariableW\""}

{"name":"$s69","value":"\"FreeEnvironmentStringsW\""}

{"name":"$s70","value":"\"GetEnvironmentStringsW\""}

{"name":"$s71","value":"\"SetEnvironmentVariableW\""}

{"name":"$s72","value":"\"GetSystemInfo\""}

{"name":"$s73","value":"\"QueryPerformanceFrequency\""}

{"name":"$s74","value":"\"QueryPerformanceCounter\""}

{"name":"$s75","value":"\"CreateProcessW\""}

{"name":"$s76","value":"\"GetStdHandle\""}

{"name":"$s77","value":"\"GetHandleInformation\""}

{"name":"$s78","value":"\"SetHandleInformation\""}

{"name":"$s79","value":"\"WriteFile\""}

{"name":"$s80","value":"\"GetConsoleOutputCP\""}

{"name":"$s81","value":"\"FreeLibrary\""}

{"name":"$s82","value":"\"GetConsoleScreenBufferInfo\""}

{"name":"$s83","value":"\"MultiByteToWideChar\""}

{"name":"$s84","value":"\"RaiseException\""}

{"name":"$s85","value":"\"RtlUnwind\""}

{"name":"$s86","value":"\"GetCurrentDirectoryW\""}

{"name":"$s87","value":"\"IsDebuggerPresent\""}

{"name":"$s88","value":"\"LocalFree\""}

{"name":"$s89","value":"\"WideCharToMultiByte\""}

{"name":"$s90","value":"\"GetCommandLineW\""}

{"name":"$s91","value":"\"ReadFile\""}

{"name":"$s92","value":"\"GetFileSize\""}

{"name":"$s93","value":"\"CloseHandle\""}

{"name":"$s94","value":"\"CreateFileW\""}

{"name":"$s95","value":"\"LoadLibraryW\""}

{"name":"$s96","value":"\"GetProcAddress\""}

{"name":"$s97","value":"\"GetFileAttributesW\""}

{"name":"$s98","value":"\"GetLastError\""}

{"name":"$s99","value":"\"CommandLineToArgvW\""}

{"name":"$s100","value":"\"MessageBoxA\""}

{"name":"$s101","value":"\"RegEnumValueW\""}

{"name":"$s102","value":"\"RegEnumKeyExW\""}

{"name":"$s103","value":"\"RegDeleteValueW\""}

{"name":"$s104","value":"\"RegFlushKey\""}

{"name":"$s105","value":"\"RegQueryInfoKeyW\""}

{"name":"$s106","value":"\"RegDeleteKeyW\""}

{"name":"$s107","value":"\"RegQueryValueExW\""}

{"name":"$s108","value":"\"RegSetValueExW\""}

{"name":"$s109","value":"\"RegOpenKeyW\""}

{"name":"$s110","value":"\"RegOpenKeyExW\""}

{"name":"$s111","value":"\"RegCreateKeyExW\""}

{"name":"$s112","value":"\"RegCloseKey\""}

Threat Analysis

This YARA rule is designed to detect general threats.

Severity Level: High

The rule uses pattern matching to identify specific byte sequences, strings, or behavioral patterns associated with malicious activity.

Detection Capabilities

File-based detection for executables and documents
Memory scanning for running processes
Network traffic analysis support

Command Line Usage

# Scan a single file
yara APT_Backdoor_Win_DShell_1.yar /path/to/suspicious/file

# Scan a directory recursively
yara -r APT_Backdoor_Win_DShell_1.yar /path/to/directory/

# Scan with metadata output
yara -m APT_Backdoor_Win_DShell_1.yar target_file

# Scan process memory (Linux)
yara APT_Backdoor_Win_DShell_1.yar /proc/[pid]/exe

Integration Examples

Python (yara-python)

import yara
rules = yara.compile(filepath='APT_Backdoor_Win_DShell_1.yar')
matches = rules.match('/path/to/file')

ClamAV Integration

clamscan --yara-rules=APT_Backdoor_Win_DShell_1.yar /path/to/scan

Rule Information

YARA ID

YARA-2025-1032

Author

FireEye

Repository

fireeye_red_team_tool_countermeasures

Created

August 19, 2025

Last Updated

August 19, 2025

Last Imported

Never

Threat Intelligence

Risk Level High

Category general

Detection Confidence Analysis Pending

False Positive Rate Not Available

Last Seen in Wild No Data

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APT_Backdoor_Win_DShell_1

Rule Metadata

String Definitions

Threat Analysis

Detection Capabilities

Command Line Usage

Integration Examples

Python (yara-python)

ClamAV Integration

Rule Information

Threat Intelligence

Related Rules

Export Options

Similar Rules in general

Detect_Mimic_Ransomware

SystemBC_malware

detect_catB

detect_Typhon_Stealer

Nosu_stealer

detect_Lumma_stealer

detect_StrelaStealer

detect_silence_Downloader