mshtml.dll

Microsoft (R) HTML Viewer file version info (xCyclopedia)

LOLBAS Execute 1 ATT&CK technique 1 documented command 2 known copies with hashes

How mshtml.dll is abused

documented by LOLBAS

Execute T1218.011 System Binary Proxy Execution: Rundll32

Run by rundll32.exe: mshtml.dll,printhtml

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

1 documented command

from LOLBAS, each read by the identifier

Execute T1218.011 System Binary Proxy Execution: Rundll32 User privileges

Invoke an HTML Application via mshta.exe (note: pops a security warning and a print dialogue box).

rundll32.exe Mshtml.dll,PrintHTML {PATH_ABSOLUTE:.hta}

Identify

Trips 1 Sigma rule: mediumPotentially Suspicious Rundll32 Activity by juju4, Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)

The command the identifier reads trips a Sigma process-creation rule. These commands and their descriptions are from LOLBAS’s entry for mshtml.dll, by LOLBAS Team, 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 mshtml.dll. 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

T1218.011System Binary Proxy Execution: Rundll32

Is it the real mshtml.dll?

file version info and known copies

Installed inC:\Windows\system32\
C:\Windows\SysWOW64\

Signed byMicrosoft Windows

ProductInternet Explorer, Microsoft Corporation

DescriptionMicrosoft (R) HTML Viewer

2 known copies

11.00.19041.508 (WinBuild.160101.0800) · C:\Windows\SysWOW64\mshtml.dll · signed by Microsoft Windows

47ddaa6888e7df9490da5fa3a15e9f6cac38bab927aee810d0db5baeabbd82ea

11.00.19041.1 (WinBuild.160101.0800) · C:\Windows\system32\mshtml.dll · signed by Microsoft Windows

3d95fba53ed28b7b87543adfc7a9f48bdcbe7b48f245300b982cc07e4b2392c7

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.