Analysis
- max time kernel
898s - max time network
889s - platform
windows10-ltsc_2021_x64 - resource
win10ltsc2021-20260911-en - resource tags
arch:x64arch:x86image:win10ltsc2021-20260911-enlocale:en-usos:windows10-ltsc_2021-x64systemwindows - submitted
16/09/2026, 22:40
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
- Sample260916-2l2mfsweph
- 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 behavioral2/memory/3248-0-0x0000000000240000-0x0000000000252000-memory.dmp family_neptunerat behavioral2/files/0x001c000000010230-2.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-1-5-21-4003929486-1233426720-3594832368-1000\Control Panel\International\Geo\Nation MasonClient.exe - Executes dropped EXE 16 IoCs
pid Process 3096 MasonClient.exe 3156 MasonClient.exe 4928 MasonClient.exe 2120 MasonClient.exe 3580 MasonClient.exe 1564 MasonClient.exe 452 MasonClient.exe 4240 MasonClient.exe 4508 MasonClient.exe 5092 MasonClient.exe 3376 MasonClient.exe 3752 MasonClient.exe 3732 MasonClient.exe 640 MasonClient.exe 1588 MasonClient.exe 4932 MasonClient.exe - Adds Run key to start application 2 TTPs 1 IoCs
description ioc Process Set value (str) \REGISTRY\USER\S-1-5-21-4003929486-1233426720-3594832368-1000\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 2580 schtasks.exe - Suspicious use of AdjustPrivilegeToken 17 IoCs
description pid Process Token: SeDebugPrivilege 3248 MasonClient.exe Token: SeDebugPrivilege 3096 MasonClient.exe Token: SeDebugPrivilege 3156 MasonClient.exe Token: SeDebugPrivilege 4928 MasonClient.exe Token: SeDebugPrivilege 2120 MasonClient.exe Token: SeDebugPrivilege 3580 MasonClient.exe Token: SeDebugPrivilege 1564 MasonClient.exe Token: SeDebugPrivilege 452 MasonClient.exe Token: SeDebugPrivilege 4240 MasonClient.exe Token: SeDebugPrivilege 4508 MasonClient.exe Token: SeDebugPrivilege 5092 MasonClient.exe Token: SeDebugPrivilege 3376 MasonClient.exe Token: SeDebugPrivilege 3752 MasonClient.exe Token: SeDebugPrivilege 3732 MasonClient.exe Token: SeDebugPrivilege 640 MasonClient.exe Token: SeDebugPrivilege 1588 MasonClient.exe Token: SeDebugPrivilege 4932 MasonClient.exe - Suspicious use of WriteProcessMemory 1 IoCs
description pid Process procid_target PID 3248 wrote to memory of 2580 3248 MasonClient.exe 82 - 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:3248 -
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:2580
-
-
C:\Users\Admin\AppData\Roaming\MasonClient.exeC:\Users\Admin\AppData\Roaming\MasonClient.exe1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3096
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3156
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4928
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:2120
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3580
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:1564
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:452
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4240
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4508
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:5092
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3376
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3752
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:3732
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:640
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:1588
-
C:\Users\Admin\AppData\Roaming\MasonClient.exe"C:\Users\Admin\AppData\Roaming\MasonClient.exe"1⤵
- Executes dropped EXE
- Suspicious use of AdjustPrivilegeToken
PID:4932
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 d39a78fabca39532fcb85ce908781a75132e1bd01cc50a3b290dd87127837d63
- MD5 11c6e74f0561678d2cf7fc075a6cc00c
- SHA1 535ee79ba978554abcb98c566235805e7ea18490
- SHA512 32c63d67bf512b42e7f57f71287b354200126cb417ef9d869c72e0b9388a7c2f5e3b61f303f1353baa1bf482d0f17e06e23c9f50b2f1babd4d958b6da19c40b0
- TLSH T136F0783432A2E1D5C9127F111C1D298452AF8386B6A0AF1C7A68935DD8261376F313F3
- 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