15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394

Virtualization/Sandbox Evasion

T1497

description	ioc	Process
Key opened	\REGISTRY\MACHINE\HARDWARE\ACPI\DSDT\VBOX__	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key opened	\REGISTRY\MACHINE\HARDWARE\ACPI\DSDT\VBOX__	csrss.exe

Checks BIOS information in registry 2 TTPs 4 IoCs

BIOS information is often read in order to detect sandboxing environments.

Query Registry

System Information Discovery

description	ioc	Process
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\SystemBiosVersion	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\VideoBiosVersion	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\SystemBiosVersion	csrss.exe
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\VideoBiosVersion	csrss.exe

Checks computer location settings 2 TTPs 2 IoCs

Looks up country code configured in the registry, likely geofence.

Query Registry

System Information Discovery

description	ioc	Process
Key value queried	\REGISTRY\USER\S-1-5-21-240542094-4193773837-3211495583-1000\Control Panel\International\Geo\Nation	csrss.exe
Key value queried	\REGISTRY\USER\S-1-5-21-240542094-4193773837-3211495583-1000\Control Panel\International\Geo\Nation	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe

Executes a file named after a Windows system binary 1 TTPs 1 IoCs

The file runs from a user directory while carrying the name of an executable that normally only exists in System32.

defense_evasion

Match Legitimate Name or Location

T1036.005

description	ioc	Process
File opened (read-only)	C:\Users\Admin\AppData\Local\Temp\Microsoft_update\csrss.exe	csrss.exe

Checks whether UAC is enabled 1 TTPs 2 IoCs

defense_evasion trojan

System Information Discovery

description	ioc	Process
Key value queried	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key value queried	\REGISTRY\MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA	csrss.exe

Writes to the Master Boot Record (MBR) 1 TTPs 2 IoCs

Bootkits write to the MBR to gain persistence at a level below the operating system.

bootkit persistence

Bootkit

T1542.003

description	ioc	Process
File opened for modification	\??\PhysicalDrive0	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
File opened for modification	\??\PhysicalDrive0	csrss.exe

Suspicious use of NtSetInformationThreadHideFromDebugger 1 TTPs 2 IoCs

defense_evasion

Debugger Evasion

T1622

pid	Process
2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
4644	csrss.exe

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

System Information Discovery
T1082

Reads the TCP/IP host and domain name from the registry 1 TTPs 2 IoCs

The configured hostname and DNS domain identify the machine and are commonly collected to profile a host before it reports in.

discovery

System Network Configuration Discovery

T1016

description	ioc	Process
Key value queried	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Hostname	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key value queried	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Domain	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe

System Location Discovery: System Language Discovery 1 TTPs 4 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	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	schtasks.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	csrss.exe
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	schtasks.exe

Checks processor information in registry 2 TTPs 2 IoCs

Processor information is often read in order to detect sandboxing environments.

Query Registry

System Information Discovery

description	ioc	Process
Key opened	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0\ProcessorNameString	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe

Scheduled Task/Job: Scheduled Task 1 TTPs 2 IoCs

Schtasks is often used by malware for persistence or to perform post-infection execution.

persistence execution

Scheduled Task

pid	Process
1896	schtasks.exe
2532	schtasks.exe

Suspicious behavior: EnumeratesProcesses 4 IoCs

pid	Process
2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
4644	csrss.exe
4644	csrss.exe

Suspicious behavior: RenamesItself 2 IoCs

pid	Process
2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
4644	csrss.exe

Suspicious use of SetWindowsHookEx 2 IoCs

pid	Process
2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
4644	csrss.exe

Suspicious use of WriteProcessMemory 2 IoCs

description	pid	Process	procid_target
PID 2856 wrote to memory of 1896	2856	15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe	87
PID 4644 wrote to memory of 2532	4644	csrss.exe	92

C:\Users\Admin\AppData\Local\Temp\15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe
"C:\Users\Admin\AppData\Local\Temp\15778b90a7efc086d8f1a26b32bb894fb82217148a2c2e4d51f66f4eeb43f394.exe"
1⤵
- Identifies VirtualBox via ACPI registry values (likely anti-VM)
- Checks BIOS information in registry
- Checks computer location settings
- Checks whether UAC is enabled
- Writes to the Master Boot Record (MBR)
- Suspicious use of NtSetInformationThreadHideFromDebugger
- Reads the TCP/IP host and domain name from the registry
- System Location Discovery: System Language Discovery
- Checks processor information in registry
- Suspicious behavior: EnumeratesProcesses
- Suspicious behavior: RenamesItself
- Suspicious use of SetWindowsHookEx
- Suspicious use of WriteProcessMemory
PID:2856
- C:\Windows\SysWOW64\schtasks.exe
  "C:\Windows\System32\schtasks.exe" /Create /F /TN "MicrosoftEdgeUpdateTaskMachineCore" /TR "\"C:\Users\Admin\AppData\Local\Temp\Microsoft_update\csrss.exe\"" /SC MINUTE /MO 30 /RU SYSTEM /RL HIGHEST
  2⤵
  - System Location Discovery: System Language Discovery
  - Scheduled Task/Job: Scheduled Task
  PID:1896

C:\Users\Admin\AppData\Local\Temp\Microsoft_update\csrss.exe
"C:\Users\Admin\AppData\Local\Temp\Microsoft_update\csrss.exe"
1⤵
- Identifies VirtualBox via ACPI registry values (likely anti-VM)
- Checks BIOS information in registry
- Checks computer location settings
- Executes a file named after a Windows system binary
- Checks whether UAC is enabled
- Writes to the Master Boot Record (MBR)
- Suspicious use of NtSetInformationThreadHideFromDebugger
- System Location Discovery: System Language Discovery
- Suspicious behavior: EnumeratesProcesses
- Suspicious behavior: RenamesItself
- Suspicious use of SetWindowsHookEx
- Suspicious use of WriteProcessMemory
PID:4644
- C:\Windows\SysWOW64\schtasks.exe
  "C:\Windows\System32\schtasks.exe" /Create /F /TN "MicrosoftEdgeUpdateTaskMachineCore" /TR "\"C:\Users\Admin\AppData\Local\Temp\Microsoft_update\csrss.exe\"" /SC MINUTE /MO 30 /RU SYSTEM /RL HIGHEST
  2⤵
  - System Location Discovery: System Language Discovery
  - Scheduled Task/Job: Scheduled Task
  PID:2532

Network

MITRE ATT&CK Enterprise v16

Reconnaissance

Resource Development

Initial Access

Execution

Scheduled Task/Job

T1053

Scheduled Task

Persistence

Pre-OS Boot

T1542

Bootkit

T1542.003

Scheduled Task/Job

T1053

Scheduled Task

Privilege Escalation

Scheduled Task/Job

T1053

Scheduled Task

Defense Evasion

Debugger Evasion

T1622

Masquerading

T1036

Match Legitimate Name or Location

T1036.005

Pre-OS Boot

T1542

Bootkit

T1542.003

Virtualization/Sandbox Evasion

T1497

Credential Access

Discovery

Debugger Evasion

T1622

Query Registry

System Information Discovery