Analysis
- user interaction
yes - max time kernel
898s - max time network
889s - platform
windows10-2004_x64 - resource
win10v2004-20260911-en - resource tags
arch:x64arch:x86image:win10v2004-20260911-enlocale:en-usos:windows10-2004-x64systemwindows - submitted
16/09/2026, 22:39
Behavioral task
behavioral1
Sample
MasonClient.exe
Resource
win10v2004-20260911-en
Behavioral task
behavioral2
Sample
MasonClient.exe
Resource
win10ltsc2021-20260911-en
Behavioral task
behavioral3
Sample
MasonClient.exe
Resource
win11-20260911-en
Behavioral task
behavioral4
Sample
MasonClient.exe
Resource
win11ltsc2024-20260911-en
General
- Target MasonClient.exe
- Size 49KB
- Sample260916-2k66jsfb63
- SHA256 3fd1677145bc6e50d8b9d26d5369360e84c9063edcf8aae7972ee029fd0d5e83
- MD5 d124ff038191eb90d3c747b945d3307f
- SHA1 8284b61252268780fb732a4b16d84193dc6e005d
- SHA512 08c32c463820de1d3bcaf456dac9354826aae098ebab4cf98581006ff13f39f980728aad41a9b268f5eecf73211ab9f05072e29ecf77d906a9221d68201e187b
- SSDEEP 1536:C3HEr1GtUtfuUnUk7XUNo57qp1XOcCXOchXOc8XOcVXOc1DVwZUOmUk+KmSKmwXP:C3HEr1GtUtfuUnUk7XUaZqp1XOcCXOc1
- TLSH T12733E78DE7D50121D6BF9EB119B31209C3B07AD34916C66F7CD841CB2B2BB984681BE7
- MD5 SHA1 SHA512 SSDEEP TLSH
Malware Config
Extracted
-
neptunerat
-
188.209.211.120:8080
-
filename
USB.exe
-
group
MasonGroup
-
key
dzLRNpkgEBxWJ2Jm
-
rat_name
MasonRAT
Signatures
- Family: NeptuneRAT, MasonRAT
NeptuneRAT aka MasonRAT is a trojan written in C#.
- Detects NeptuneRAT stealer 2 IoCs
resource yara_rule behavioral1/memory/4540-0-0x0000000000E30000-0x0000000000E42000-memory.dmp family_neptunerat behavioral1/files/0x000a0000000243d4-3.dat family_neptunerat - Checks computer location settings 2 TTPs 1 IoCs
Looks up country code configured in the registry, likely geofence.
description ioc Process Key value queried \REGISTRY\USER\S-1-5-21-747854149-4118156852-591593384-1000\Control Panel\International\Geo\Nation MasonClient.exe - Executes dropped EXE 16 IoCs
pid Process 3580 MasonClient.exe 3916 MasonClient.exe 1396 MasonClient.exe 4064 MasonClient.exe 5052 MasonClient.exe 444 MasonClient.exe 2404 MasonClient.exe 4164 MasonClient.exe 4860 MasonClient.exe 2656 MasonClient.exe 4712 MasonClient.exe 4888 MasonClient.exe 1292 MasonClient.exe 2812 MasonClient.exe 4332 MasonClient.exe 1668 MasonClient.exe - Adds Run key to start application 2 TTPs 1 IoCs
description ioc Process Set value (str) \REGISTRY\USER\S-1-5-21-747854149-4118156852-591593384-1000\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\MasonClient = "C:\\Users\\Admin\\AppData\\Roaming\\MasonClient.exe" MasonClient.exe - Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s).
- Scheduled Task/Job: Scheduled Task 1 TTPs 1 IoCs
Schtasks is often used by malware for persistence or to perform post-infection execution.
pid Process 1808 schtasks.exe - Suspicious use of AdjustPrivilegeToken 17 IoCs
description pid Process Token: SeDebugPrivilege 4540 MasonClient.exe Token: SeDebugPrivilege 3580 MasonClient.exe Token: SeDebugPrivilege 3916 MasonClient.exe Token: SeDebugPrivilege 1396 MasonClient.exe Token: SeDebugPrivilege 4064 MasonClient.exe Token: SeDebugPrivilege 5052 MasonClient.exe Token: SeDebugPrivilege 444 MasonClient.exe Token: SeDebugPrivilege 2404 MasonClient.exe Token: SeDebugPrivilege 4164 MasonClient.exe Token: SeDebugPrivilege 4860 MasonClient.exe Token: SeDebugPrivilege 2656 MasonClient.exe Token: SeDebugPrivilege 4712 MasonClient.exe Token: SeDebugPrivilege 4888 MasonClient.exe Token: SeDebugPrivilege 1292 MasonClient.exe Token: SeDebugPrivilege 2812 MasonClient.exe Token: SeDebugPrivilege 4332 MasonClient.exe Token: SeDebugPrivilege 1668 MasonClient.exe - Suspicious use of WriteProcessMemory 1 IoCs
description pid Process procid_target PID 4540 wrote to memory of 1808 4540 MasonClient.exe 85 - Uses Task Scheduler COM API 1 TTPs
The Task Scheduler COM API can be used to schedule applications to run on boot or at set times.
Processes
-
C:\Users\Admin\AppData\Local\Temp\MasonClient.exe"C:\Users\Admin\AppData\Local\Temp\MasonClient.exe"1⤵
- Checks computer location settings
- Adds Run key to start application
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
PID:4540 -
C:\Windows\System32\schtasks.exe"C:\Windows\System32\schtasks.exe" /create /f /sc minute /mo 1 /tn "MasonClient" /tr "C:\Users\Admin\AppData\Roaming\MasonClient.exe"2⤵
- Scheduled Task/Job: Scheduled Task
PID:1808
-
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3580
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3916
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:1396
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4064
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:5052
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:444
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:2404
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4164
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4860
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:2656
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4712
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4888
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:1292
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:2812
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4332
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:1668
Network
MITRE ATT&CK Enterprise v16
Persistence
Boot or Logon Autostart Execution
1Registry Run Keys / Startup Folder
1Scheduled Task/Job
1Scheduled Task
1Replay Monitor
Loading Replay Monitor...
Downloads
- Path C:\Users\Admin\AppData\Local\Microsoft\CLR_v4.0\UsageLogs\MasonClient.exe.log
- Size 654B
- SHA256 e1b91642d85d98124a6a31f710e137ab7fd90dec30e74a05ab7fcf3b7887dced
- MD5 2ff39f6c7249774be85fd60a8f9a245e
- SHA1 684ff36b31aedc1e587c8496c02722c6698c1c4e
- SHA512 1d7e8b92ef4afd463d62cfa7e8b9d1799db5bf2a263d3cd7840df2e0a1323d24eb595b5f8eb615c6cb15f9e3a7b4fc99f8dd6a3d34479222e966ec708998aed1
- TLSH T1D9F0DD242221E1C489127F111C0D2A4452BF4797B760EE0C7554529FD8312275F203E7
- MD5 SHA1 SHA512 TLSH
- Path C:\Users\Admin\AppData\Roaming\MasonClient.exe
- Size 49KB
- SHA256 3fd1677145bc6e50d8b9d26d5369360e84c9063edcf8aae7972ee029fd0d5e83
- MD5 d124ff038191eb90d3c747b945d3307f
- SHA1 8284b61252268780fb732a4b16d84193dc6e005d
- SHA512 08c32c463820de1d3bcaf456dac9354826aae098ebab4cf98581006ff13f39f980728aad41a9b268f5eecf73211ab9f05072e29ecf77d906a9221d68201e187b
- SSDEEP 1536:C3HEr1GtUtfuUnUk7XUNo57qp1XOcCXOchXOc8XOcVXOc1DVwZUOmUk+KmSKmwXP:C3HEr1GtUtfuUnUk7XUaZqp1XOcCXOc1
- TLSH T12733E78DE7D50121D6BF9EB119B31209C3B07AD34916C66F7CD841CB2B2BB984681BE7
- MD5 SHA1 SHA512 SSDEEP TLSH