Malware Analysis Report

2025-01-02 07:31

Sample ID 240815-v8nwjsvaqb
Target b778d988c1488f76d50f8ff1cd1bf1a0N.exe
SHA256 46951b0b1862936557aa8b0154ad81485eb20b60ff694568ff94f03009d2dc05
Tags
floxif backdoor discovery persistence trojan upx
score
10/10

Table of Contents

Analysis Overview

MITRE ATT&CK

Enterprise Matrix V15

Analysis: static1

Detonation Overview

Signatures

Analysis: behavioral2

Detonation Overview

Command Line

Signatures

Processes

Network

Files

Analysis: behavioral1

Detonation Overview

Command Line

Signatures

Processes

Network

Files

Analysis Overview

score
10/10

SHA256

46951b0b1862936557aa8b0154ad81485eb20b60ff694568ff94f03009d2dc05

Threat Level: Known bad

The file b778d988c1488f76d50f8ff1cd1bf1a0N.exe was found to be: Known bad.

Malicious Activity Summary

floxif backdoor discovery persistence trojan upx

Floxif, Floodfix

Detects Floxif payload

Loads dropped DLL

ACProtect 1.3x - 1.4x DLL software

Modifies system executable filetype association

UPX packed file

Drops file in Program Files directory

System Location Discovery: System Language Discovery

Suspicious use of AdjustPrivilegeToken

Modifies registry class

Suspicious use of WriteProcessMemory

MITRE ATT&CK

Analysis: static1

Detonation Overview

Reported

2024-08-15 17:39

Signatures

N/A

Analysis: behavioral2

Detonation Overview

Submitted

2024-08-15 17:39

Reported

2024-08-15 17:41

Platform

win10v2004-20240802-en

Max time kernel

78s

Max time network

80s

Command Line

regsvr32 /s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

Signatures

Floxif, Floodfix

backdoor trojan floxif

Detects Floxif payload

backdoor
Description Indicator Process Target
N/A N/A N/A N/A

ACProtect 1.3x - 1.4x DLL software

Description Indicator Process Target
N/A N/A N/A N/A

Loads dropped DLL

Description Indicator Process Target
N/A N/A C:\Windows\SysWOW64\regsvr32.exe N/A
N/A N/A C:\Windows\SysWOW64\regsvr32.exe N/A

Modifies system executable filetype association

persistence
Description Indicator Process Target
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A

UPX packed file

upx
Description Indicator Process Target
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A

Drops file in Program Files directory

Description Indicator Process Target
File created C:\Program Files\Common Files\System\symsrv.dll C:\Windows\SysWOW64\regsvr32.exe N/A

System Location Discovery: System Language Discovery

discovery
Description Indicator Process Target
Key opened \REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language C:\Windows\SysWOW64\regsvr32.exe N/A

Modifies registry class

Description Indicator Process Target
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32 C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Msi.Package\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Msi.Package\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\ = "RUShellExt Class" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7} C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\RUExt.DLL\AppID = "{1D928D64-60D3-4FAC-B810-C4D9D8A680CF}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Folder\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Folder\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32\ = "C:\\Users\\Admin\\AppData\\Local\\Temp\\b778d988c1488f76d50f8ff1cd1bf1a0N.dll" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\{1D928D64-60D3-4FAC-B810-C4D9D8A680CF}\ = "RUExt" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\RUExt.DLL C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32\ThreadingModel = "Apartment" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\{1D928D64-60D3-4FAC-B810-C4D9D8A680CF} C:\Windows\SysWOW64\regsvr32.exe N/A

Suspicious use of AdjustPrivilegeToken

Description Indicator Process Target
Token: SeDebugPrivilege N/A C:\Windows\SysWOW64\regsvr32.exe N/A

Suspicious use of WriteProcessMemory

Description Indicator Process Target
PID 1264 wrote to memory of 2260 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 1264 wrote to memory of 2260 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 1264 wrote to memory of 2260 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe

Processes

C:\Windows\system32\regsvr32.exe

regsvr32 /s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

C:\Windows\SysWOW64\regsvr32.exe

/s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

Network

Country Destination Domain Proto
US 8.8.8.8:53 17.53.126.40.in-addr.arpa udp
US 8.8.8.8:53 104.219.191.52.in-addr.arpa udp
US 8.8.8.8:53 88.156.103.20.in-addr.arpa udp
US 8.8.8.8:53 154.239.44.20.in-addr.arpa udp
US 8.8.8.8:53 103.169.127.40.in-addr.arpa udp
US 8.8.8.8:53 171.39.242.20.in-addr.arpa udp
US 8.8.8.8:53 40.140.123.92.in-addr.arpa udp
US 8.8.8.8:53 tse1.mm.bing.net udp
US 150.171.28.10:443 tse1.mm.bing.net tcp
US 150.171.28.10:443 tse1.mm.bing.net tcp
US 150.171.28.10:443 tse1.mm.bing.net tcp
US 150.171.28.10:443 tse1.mm.bing.net tcp
US 150.171.28.10:443 tse1.mm.bing.net tcp
US 8.8.8.8:53 57.169.31.20.in-addr.arpa udp
US 8.8.8.8:53 10.28.171.150.in-addr.arpa udp
US 8.8.8.8:53 0.204.248.87.in-addr.arpa udp
US 8.8.8.8:53 11.227.111.52.in-addr.arpa udp

Files

C:\Program Files\Common Files\System\symsrv.dll

MD5 7574cf2c64f35161ab1292e2f532aabf
SHA1 14ba3fa927a06224dfe587014299e834def4644f
SHA256 de055a89de246e629a8694bde18af2b1605e4b9b493c7e4aef669dd67acf5085
SHA512 4db19f2d8d5bc1c7bbb812d3fa9c43b80fa22140b346d2760f090b73aed8a5177edb4bddc647a6ebd5a2db8565be5a1a36a602b0d759e38540d9a584ba5896ab

memory/2260-6-0x0000000001390000-0x00000000013C0000-memory.dmp

memory/2260-8-0x0000000001390000-0x00000000013C0000-memory.dmp

Analysis: behavioral1

Detonation Overview

Submitted

2024-08-15 17:39

Reported

2024-08-15 17:41

Platform

win7-20240708-en

Max time kernel

117s

Max time network

118s

Command Line

regsvr32 /s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

Signatures

Floxif, Floodfix

backdoor trojan floxif

Detects Floxif payload

backdoor
Description Indicator Process Target
N/A N/A N/A N/A

ACProtect 1.3x - 1.4x DLL software

Description Indicator Process Target
N/A N/A N/A N/A

Loads dropped DLL

Description Indicator Process Target
N/A N/A C:\Windows\SysWOW64\regsvr32.exe N/A

Modifies system executable filetype association

persistence
Description Indicator Process Target
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A

UPX packed file

upx
Description Indicator Process Target
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A

Drops file in Program Files directory

Description Indicator Process Target
File created C:\Program Files\Common Files\System\symsrv.dll C:\Windows\SysWOW64\regsvr32.exe N/A

System Location Discovery: System Language Discovery

discovery
Description Indicator Process Target
Key opened \REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language C:\Windows\SysWOW64\regsvr32.exe N/A

Modifies registry class

Description Indicator Process Target
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32 C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\{1D928D64-60D3-4FAC-B810-C4D9D8A680CF} C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\RUExt.DLL\AppID = "{1D928D64-60D3-4FAC-B810-C4D9D8A680CF}" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\ = "RUShellExt Class" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32\ = "C:\\Users\\Admin\\AppData\\Local\\Temp\\b778d988c1488f76d50f8ff1cd1bf1a0N.dll" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}\InprocServer32\ThreadingModel = "Apartment" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Folder\ShellEx\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\{1D928D64-60D3-4FAC-B810-C4D9D8A680CF}\ = "RUExt" C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\Msi.Package\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\AppID\RUExt.DLL C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Wow6432Node\CLSID\{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7} C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\exefile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Msi.Package\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A
Set value (str) \REGISTRY\MACHINE\SOFTWARE\Classes\lnkfile\shellex\ContextMenuHandlers\RUShellExt\ = "{2C5515DC-2A7E-4BFD-B813-CACC2B685EB7}" C:\Windows\SysWOW64\regsvr32.exe N/A
Key created \REGISTRY\MACHINE\SOFTWARE\Classes\Folder\ShellEx\ContextMenuHandlers\RUShellExt C:\Windows\SysWOW64\regsvr32.exe N/A

Suspicious use of AdjustPrivilegeToken

Description Indicator Process Target
Token: SeDebugPrivilege N/A C:\Windows\SysWOW64\regsvr32.exe N/A

Suspicious use of WriteProcessMemory

Description Indicator Process Target
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe
PID 2624 wrote to memory of 2076 N/A C:\Windows\system32\regsvr32.exe C:\Windows\SysWOW64\regsvr32.exe

Processes

C:\Windows\system32\regsvr32.exe

regsvr32 /s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

C:\Windows\SysWOW64\regsvr32.exe

/s C:\Users\Admin\AppData\Local\Temp\b778d988c1488f76d50f8ff1cd1bf1a0N.dll

Network

N/A

Files

\Program Files\Common Files\System\symsrv.dll

MD5 7574cf2c64f35161ab1292e2f532aabf
SHA1 14ba3fa927a06224dfe587014299e834def4644f
SHA256 de055a89de246e629a8694bde18af2b1605e4b9b493c7e4aef669dd67acf5085
SHA512 4db19f2d8d5bc1c7bbb812d3fa9c43b80fa22140b346d2760f090b73aed8a5177edb4bddc647a6ebd5a2db8565be5a1a36a602b0d759e38540d9a584ba5896ab

memory/2076-3-0x0000000000260000-0x0000000000290000-memory.dmp

memory/2076-5-0x0000000000260000-0x0000000000290000-memory.dmp