mofksys | 543f44441b581cd96a4d0d295b213be8429d98fb42afa187058e8dff428f7b6d

Analysis

max time kernel
150s
max time network
126s
platform
windows11-ltsc_2024_x64
resource
win11ltsc2024-20260911-en
resource tags

arch:x64arch:x86image:win11ltsc2024-20260911-enlocale:en-usos:windows11-ltsc_2024-x64systemwindows
submitted
11/11/2026, 22:44

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General

Target
543f44441b581cd9.exe
Size 206KB
Sample261111-2nr6sscd83
SHA256 543f44441b581cd96a4d0d295b213be8429d98fb42afa187058e8dff428f7b6d
MD5 19cb653f16093cfaa222b95cd655a177
SHA1 f0d6cd2e6cb9581ef434ce30dedaebe6fed43ac1
SHA512 319d79e36ff7d186c45681c33510a75c403c86cc603b9b2464b6000879f1512b10224eb9bf91104447af63e29fb096e66915fad7a9848ba5d5964129c88bdf59
SSDEEP 3072:5vEfVUzSLhIVbV6i5LirrlZrHyrUHUckoMQ2RN6unGd:5vEN2U+T6i5LirrllHy4HUcMQY6Jd
TLSH
T17124E82BFA40B17FD4A7C6F0582572A6BA252D621B90DC4F22D26F463876543B6F130F
MD5 SHA1 SHA512 SSDEEP TLSH

Score

10^/10

defense_evasion discovery mofksys persistence worm

Malware Config

Signatures

Family: Mofksys
Mofksys is a worm written in VisualBasic.
worm mofksys

Detects Mofksys worm 10 IoCs

resource	yara_rule
behavioral2/memory/4052-0-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys
behavioral2/files/0x000e00000001c609-7.dat	family_mofksys
behavioral2/files/0x000d00000001c60f-17.dat	family_mofksys
behavioral2/files/0x000d00000001c612-26.dat	family_mofksys
behavioral2/memory/4744-35-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys
behavioral2/memory/1228-38-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys
behavioral2/files/0x000d00000001c615-39.dat	family_mofksys
behavioral2/memory/4052-40-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys
behavioral2/memory/4640-41-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys
behavioral2/memory/4500-42-0x0000000000400000-0x0000000000440000-memory.dmp	family_mofksys

Modifies WinLogon for persistence 2 TTPs 2 IoCs

persistence

Winlogon Helper DLL

T1547.004

Modify Registry

T1112

description	ioc	Process
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon\shell = "C:\\Windows\\explorer.exe, c:\\windows\\system\\explorer.exe"	explorer.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\Winlogon\shell = "C:\\Windows\\explorer.exe, c:\\windows\\system\\explorer.exe"	svchost.exe

Modifies visibility of hidden/system files in Explorer 2 TTPs 2 IoCs

defense_evasion

Hidden Files and Directories

T1564.001

Modify Registry

T1112

description	ioc	Process
Set value (int)	\REGISTRY\USER\S-1-5-21-1404337215-1550464601-2805570857-1000\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\ShowSuperHidden = "0"	explorer.exe
Set value (int)	\REGISTRY\USER\S-1-5-21-1404337215-1550464601-2805570857-1000\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\ShowSuperHidden = "0"	svchost.exe

Boot or Logon Autostart Execution: Active Setup 2 TTPs 8 IoCs

Adversaries may achieve persistence by adding a Registry key to the Active Setup of the local machine.

persistence

Active Setup

T1547.014

Modify Registry

T1112

description	ioc	Process
Key created	\REGISTRY\MACHINE\Software\WOW6432Node\Microsoft\Active Setup\Installed Components\{Y479C6D0-OTRW-U5GH-S1EE-E0AC10B4E666}	svchost.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Active Setup\Installed Components\{Y479C6D0-OTRW-U5GH-S1EE-E0AC10B4E666}\StubPath = "C:\\Users\\Admin\\AppData\\Roaming\\mrsys.exe MR"	svchost.exe
Key deleted	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Active Setup\Installed Components\{F146C9B1-VMVQ-A9RC-NUFL-D0BA00B4E999}	svchost.exe
Key created	\REGISTRY\MACHINE\Software\WOW6432Node\Microsoft\Active Setup\Installed Components\{Y479C6D0-OTRW-U5GH-S1EE-E0AC10B4E666}	explorer.exe
Key deleted	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Active Setup\Installed Components\{Y479C6D0-OTRW-U5GH-S1EE-E0AC10B4E666}	svchost.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Active Setup\Installed Components\{Y479C6D0-OTRW-U5GH-S1EE-E0AC10B4E666}\StubPath = "C:\\Users\\Admin\\AppData\\Roaming\\mrsys.exe MR"	explorer.exe
Key created	\REGISTRY\MACHINE\Software\WOW6432Node\Microsoft\Active Setup\Installed Components\{F146C9B1-VMVQ-A9RC-NUFL-D0BA00B4E999}	svchost.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Active Setup\Installed Components\{F146C9B1-VMVQ-A9RC-NUFL-D0BA00B4E999}\StubPath = "C:\\Users\\Admin\\AppData\\Roaming\\mrsys.exe MR"	svchost.exe

Executes dropped EXE 4 IoCs

pid	Process
4640	explorer.exe
1228	spoolsv.exe
4500	svchost.exe
4744	spoolsv.exe

Adds Run key to start application 2 TTPs 4 IoCs

persistence

Registry Run Keys / Startup Folder

T1547.001

Modify Registry

T1112

description	ioc	Process
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\RunOnce\Explorer = "c:\\windows\\system\\explorer.exe RO"	explorer.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\RunOnce\Svchost = "c:\\windows\\system\\svchost.exe RO"	explorer.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\RunOnce\Explorer = "c:\\windows\\system\\explorer.exe RO"	svchost.exe
Set value (str)	\REGISTRY\MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\RunOnce\Svchost = "c:\\windows\\system\\svchost.exe RO"	svchost.exe

Drops file in Windows directory 6 IoCs

description	ioc	Process
File opened for modification	\??\c:\windows\system\explorer.exe	543f44441b581cd9.exe
File opened for modification	\??\c:\windows\system\spoolsv.exe	explorer.exe
File opened for modification	\??\c:\windows\system\svchost.exe	spoolsv.exe
File opened for modification	\??\c:\windows\system\explorer.exe	explorer.exe
File opened for modification	\??\c:\windows\system\svchost.exe	svchost.exe
File opened for modification	C:\Windows\system\udsys.exe	explorer.exe

Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s).

System Information Discovery
T1082

System Location Discovery: System Language Discovery 1 TTPs 8 IoCs

Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

discovery

System Language Discovery

T1614.001

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	at.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	at.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	543f44441b581cd9.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	spoolsv.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	svchost.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	at.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	explorer.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	spoolsv.exe

Suspicious behavior: EnumeratesProcesses 64 IoCs

pid	Process
4052	543f44441b581cd9.exe
4052	543f44441b581cd9.exe
4640	explorer.exe
4640	explorer.exe
4640	explorer.exe
4640	explorer.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4640	explorer.exe
4500	svchost.exe
4640	explorer.exe
4500	svchost.exe
4640	explorer.exe
4500	svchost.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4500	svchost.exe
4640	explorer.exe
4640	explorer.exe
4500	svchost.exe
4640	explorer.exe

Suspicious behavior: GetForegroundWindowSpam 2 IoCs

pid	Process
4640	explorer.exe
4500	svchost.exe

Suspicious use of SetWindowsHookEx 12 IoCs

pid	Process
4052	543f44441b581cd9.exe
4052	543f44441b581cd9.exe
4640	explorer.exe
4640	explorer.exe
1228	spoolsv.exe
1228	spoolsv.exe
4500	svchost.exe
4500	svchost.exe
4744	spoolsv.exe
4744	spoolsv.exe
4640	explorer.exe
4640	explorer.exe

Suspicious use of WriteProcessMemory 7 IoCs

description	pid	Process	procid_target
PID 4052 wrote to memory of 4640	4052	543f44441b581cd9.exe	89
PID 4640 wrote to memory of 1228	4640	explorer.exe	90
PID 1228 wrote to memory of 4500	1228	spoolsv.exe	91
PID 4500 wrote to memory of 4744	4500	svchost.exe	92
PID 4500 wrote to memory of 2852	4500	svchost.exe	93
PID 4500 wrote to memory of 4868	4500	svchost.exe	98
PID 4500 wrote to memory of 560	4500	svchost.exe	100

C:\Users\Admin\AppData\Local\Temp\543f44441b581cd9.exe
"C:\Users\Admin\AppData\Local\Temp\543f44441b581cd9.exe"
1⤵
- Drops file in Windows directory
- System Location Discovery: System Language Discovery
- Suspicious behavior: EnumeratesProcesses
- Suspicious use of SetWindowsHookEx
- Suspicious use of WriteProcessMemory
PID:4052
- \??\c:\windows\system\explorer.exe
  c:\windows\system\explorer.exe
  2⤵
  - Modifies WinLogon for persistence
  - Modifies visibility of hidden/system files in Explorer
  - Boot or Logon Autostart Execution: Active Setup
  - Executes dropped EXE
  - Adds Run key to start application
  - Drops file in Windows directory
  - System Location Discovery: System Language Discovery
  - Suspicious behavior: EnumeratesProcesses
  - Suspicious behavior: GetForegroundWindowSpam
  - Suspicious use of SetWindowsHookEx
  - Suspicious use of WriteProcessMemory
  PID:4640
- - \??\c:\windows\system\spoolsv.exe
    c:\windows\system\spoolsv.exe SE
    3⤵
    - Executes dropped EXE
    - Drops file in Windows directory
    - System Location Discovery: System Language Discovery
    - Suspicious use of SetWindowsHookEx
    - Suspicious use of WriteProcessMemory
    PID:1228
  - - \??\c:\windows\system\svchost.exe
      c:\windows\system\svchost.exe
      4⤵
      Modifies WinLogon for persistence
      Modifies visibility of hidden/system files in Explorer
      Boot or Logon Autostart Execution: Active Setup
      Executes dropped EXE
      Adds Run key to start application
      Drops file in Windows directory
      System Location Discovery: System Language Discovery
      Suspicious behavior: EnumeratesProcesses
      Suspicious behavior: GetForegroundWindowSpam
      Suspicious use of SetWindowsHookEx
      Suspicious use of WriteProcessMemory
      PID:4500
    - - \??\c:\windows\system\spoolsv.exe
        
        c:\windows\system\spoolsv.exe PR
        5⤵
        Executes dropped EXE
        System Location Discovery: System Language Discovery
        Suspicious use of SetWindowsHookEx
        
        PID:4744
    - - C:\Windows\SysWOW64\at.exe
        
        at 22:46 /interactive /every:M,T,W,Th,F,S,Su c:\windows\system\svchost.exe
        5⤵
        System Location Discovery: System Language Discovery
        
        PID:2852
    - - C:\Windows\SysWOW64\at.exe
        
        at 22:47 /interactive /every:M,T,W,Th,F,S,Su c:\windows\system\svchost.exe
        5⤵
        System Location Discovery: System Language Discovery
        
        PID:4868
    - - C:\Windows\SysWOW64\at.exe
        
        at 22:48 /interactive /every:M,T,W,Th,F,S,Su c:\windows\system\svchost.exe
        5⤵
        System Location Discovery: System Language Discovery
        
        PID:560

Network

MITRE ATT&CK Enterprise v16

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Boot or Logon Autostart Execution

T1547

Active Setup

T1547.014

Registry Run Keys / Startup Folder

T1547.001

Winlogon Helper DLL

T1547.004

Privilege Escalation

Boot or Logon Autostart Execution

T1547

Active Setup

T1547.014

Registry Run Keys / Startup Folder

T1547.001

Winlogon Helper DLL

T1547.004

Defense Evasion

Hide Artifacts

T1564

Hidden Files and Directories

T1564.001

Modify Registry

T1112

Credential Access

Discovery

System Information Discovery

T1082

System Location Discovery

T1614

System Language Discovery

T1614.001

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

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Downloads

mrsys.exe

Path C:\Users\Admin\AppData\Roaming\mrsys.exe
Size 206KB
SHA256 9e1e09f1a27b2043f272d9b5f9b6bcc83e7efd8cc40924197f9fb832ad5b6fac
MD5 e3d8b3f9460423f2eb4ddb114c9f7890
SHA1 1cf5f8b12cfca6396dafaf3fd4a698f016f5aef0
SHA512 2709b3d33cf329277a41f20c92101047c11aef26c450b9e44ae0e52b59a209d25d61f84762cf644073ac53a7b464dc49365bbac161701cfb16f16e3eff7119c9
SSDEEP 3072:5vEfVUzSLhIVbV6i5LirrlZrHyrUHUckoMQ2RN6unGk:5vEN2U+T6i5LirrllHy4HUcMQY6Jk
TLSH
T1B3240827FE04302EE8A789F1592661A6B6262D251BD0BC0F67C0AF45387191BF5F631F
MD5 SHA1 SHA512 SSDEEP TLSH

Submit Download

explorer.exe

Path C:\Windows\System\explorer.exe
Size 206KB
SHA256 9c57ed2bd2f8e4ef9dff85f1ab8b4d937637d631f0602ea41ee07bbb1c0069e0
MD5 9b5db87ed5ee652dcbc90bbf3129b370
SHA1 3b56b944979c09a6da726086a31c12e774560dca
SHA512 d06d1553c4dc63327e45a7b8f93dd4f54e0be1cba27b53eb5d49f81b3312fac666cce66d7c4e288073d0d0dc039b6f61fc7188939d1a79c6459af254bde8bd4b
SSDEEP 3072:5vEfVUzSLhIVbV6i5LirrlZrHyrUHUckoMQ2RN6unG3:5vEN2U+T6i5LirrllHy4HUcMQY6J3
TLSH
T13D24092BFB04702ED86389F09817A266BA251D351B92AC4B63C1AF0635F6513F5F532F
MD5 SHA1 SHA512 SSDEEP TLSH

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spoolsv.exe

Path C:\Windows\System\spoolsv.exe
Size 206KB
SHA256 8777c2126e28b4b71c74b5dbc8c8c6a1c0f47bb1aa8001f7a9ee711b9bc9cecb
MD5 85caa3ed82d4ed86a442c421159fe8f3
SHA1 e68703cfe9f1efae3052a540667d913b7d912fc4
SHA512 f29bf0074bd4aa89e6f335d14ec187770779c17383a3b2568f99b319f9f9dd5976bb6da5359bc6d917cde1b93d3b20831b9d35b2ae81eaf0ee3bc814e914b313
SSDEEP 3072:5vEfVUzSLhIVbV6i5LirrlZrHyrUHUckoMQ2RN6unGV:5vEN2U+T6i5LirrllHy4HUcMQY6JV
TLSH
T11624EA2BE954702ED8A396F0582675A77A362E251BD2AC0B13D0AF5738B1503F9F131F
MD5 SHA1 SHA512 SSDEEP TLSH

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svchost.exe

Path C:\Windows\System\svchost.exe
Size 206KB
SHA256 aa02f6b3ea58dcc464a570287ed3eb65b311e193125ed575c0f04dfed080be3a
MD5 2b3ce9884396bd2ba5a87fe1612fbce3
SHA1 a82a709c83bdf1abd99e32061acfd986579f1661
SHA512 005a84739017b38ba662d91bb2e6ad23a74cfd99e6faecf64fc8174053d806e9a3bf1d20b08e2025bd82496b6133514731d54a0a798315dab046d1a02819ccd9
SSDEEP 6144:5vEN2U+T6i5LirrllHy4HUcMQY6JDWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWs:RENN+T5xYrllrU7QY6JY
TLSH
T1AA24E827EA04B02FE857C9F06566F2A6BA366E211BC1DC0B66D1BB4534B1613B1F530F
MD5 SHA1 SHA512 SSDEEP TLSH

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memory/1228-38-0x0000000000400000-0x0000000000440000-memory.dmp

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memory/4052-0-0x0000000000400000-0x0000000000440000-memory.dmp

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memory/4052-40-0x0000000000400000-0x0000000000440000-memory.dmp

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memory/4500-42-0x0000000000400000-0x0000000000440000-memory.dmp

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memory/4640-41-0x0000000000400000-0x0000000000440000-memory.dmp

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memory/4744-35-0x0000000000400000-0x0000000000440000-memory.dmp

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