.. /Jsc.exe
Star

Compile (JScript)

Binary file used by .NET to compile JavaScript code to .exe or .dll format

Paths:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Jsc.exe
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Jsc.exe
C:\Windows\Microsoft.NET\Framework\v2.0.50727\Jsc.exe
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Jsc.exe

Resources:

Acknowledgements:

Malwrologist (@DissectMalware)

Detections:

Sigma: https://github.com/SigmaHQ/sigma/blob/35a7244c62820fbc5a832e50b1e224ac3a1935da/rules/windows/process_creation/proc_creation_win_lolbin_jsc.yml
IOC: Jsc.exe should normally not run a system unless it is used for development.

Compile

Use jsc.exe to compile JavaScript code stored in the provided .JS file and generate a .EXE file with the same name.
```
jsc.exe {PATH:.js}
```
Use case
Compile attacker code on system. Bypass defensive counter measures.

Privileges required
User

Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

ATT&CK® technique
T1127
Tags
Execute: JScript
Use jsc.exe to compile JavaScript code stored in the .JS file and generate a DLL file with the same name.
```
jsc.exe /t:library {PATH:.js}
```
Use case
Compile attacker code on system. Bypass defensive counter measures.

Privileges required
User

Operating systems
Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

ATT&CK® technique
T1127
Tags
Execute: JScript