Ceplin Command Identifier

Identifier / Programs / Windows

microsoft.workflow.compiler.exe

Microsoft.Workflow.Compiler.exe file version info (xCyclopedia)

LOLBAS Execute, AWL Bypass 3 Sigma rules name it 1 ATT&CK technique 3 documented commands 2 known copies with hashes

Opens the identifier with your command. It is read in your browser and sent nowhere.

How microsoft.workflow.compiler.exe is abused

documented by LOLBAS

Execute T1127 Trusted Developer Utilities Proxy Execution

AWL Bypass T1127 Trusted Developer Utilities Proxy Execution

Each abuse is LOLBAS's category and the options and words it uses; the full write-up is on LOLBAS's page for microsoft.workflow.compiler.exe.

3 documented commands

from LOLBAS, each read by the identifier

Execute T1127 Trusted Developer Utilities Proxy Execution User privileges

Compile and execute C# or VB.net code in a XOML file referenced in the first argument (any extension accepted).

Microsoft.Workflow.Compiler.exe {PATH} {PATH:.log}
Identify

Trips 1 Sigma rule: mediumMicrosoft Workflow Compiler Execution by Nik Seetharaman, frack113

Execute T1127 Trusted Developer Utilities Proxy Execution User privileges

Compile and execute C# or VB.net code in a XOML file referenced in the test.txt file.

Microsoft.Workflow.Compiler.exe {PATH} {PATH:.log}
Identify

Trips 1 Sigma rule: mediumMicrosoft Workflow Compiler Execution by Nik Seetharaman, frack113

AWL Bypass T1127 Trusted Developer Utilities Proxy Execution User privileges

Compile and execute C# or VB.net code in a XOML file referenced in the test.txt file.

Microsoft.Workflow.Compiler.exe {PATH} {PATH:.log}
Identify

Trips 1 Sigma rule: mediumMicrosoft Workflow Compiler Execution by Nik Seetharaman, frack113

All 3 commands the identifier reads trip a Sigma process-creation rule. These commands and their descriptions are from LOLBAS’s entry for microsoft.workflow.compiler.exe, by Conor Richard, at commit 2056cb766250 of 2026-09-26, under the GPL-3.0 and LOLBAS’s notice, with no warranty. Changed: Markdown is shown formatted. The source is in lolbas-gtfobins-commands.json.gz, and the full entry is on LOLBAS’s page for microsoft.workflow.compiler.exe. The identifier reads each with LOLBAS’s placeholders filled in: a URL as https://example.com/file, a share as \\192.0.2.10\share\file, a path as C:\Data\file and a command as calc.exe.

What detects it

Sigma process creation rules
highSuspicious Microsoft OneNote Child ProcessTim Rauch (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Elastic (idea)
highSuspicious Microsoft Office Child ProcessFlorian Roth (Nextron Systems), Markus Neis, FPT.EagleEye Team, Vadim Khrykov, Cyb3rEng, Michael Haag, Christopher Peacock @securepeacock, @scythe_io
mediumMicrosoft Workflow Compiler ExecutionNik Seetharaman, frack113
T1127Trusted Developer Utilities Proxy Execution

Is it the real microsoft.workflow.compiler.exe?

file version info and known copies
Installed inC:\Windows\Microsoft.NET\Framework\v4.0.30319\
Signed byMicrosoft Windows
ProductMicrosoft .NET Framework, Microsoft Corporation
DescriptionMicrosoft.Workflow.Compiler.exe

2 known copies

4.8.4161.0 built by: NET48REL1 · C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Microsoft.Workflow.Compiler.exe · signed by Microsoft Windows

585f531a76b897d0f480de1060fa962a132190524479aa2de624e6d33fca0391

4.8.4084.0 built by: NET48REL1 · C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Workflow.Compiler.exe · signed by Microsoft Windows

698be205bc3344d60a2d746d11a80174887b07fde82a01cfbb835a555064c9d9

From the file’s version info and the copies recorded by xCyclopedia (MIT). A copy in another folder, signed by someone else or with another hash is not necessarily malicious, but it is worth a closer look. In Ceplin, "<sha256>".whatis() says which known copy a hash is.