Identifier / Programs / Windows
zipfldr.dll
Compressed (zipped) Folders file version info (xCyclopedia)
LOLBAS Execute 1 ATT&CK technique 2 documented commands 2 known copies with hashes
How zipfldr.dll is abused
Execute T1218.011 System Binary Proxy Execution: Rundll32
Run by rundll32.exe: zipfldr.dll,routethecall
Each abuse is LOLBAS's category and the options and words it uses; the full write-up is on LOLBAS's page for zipfldr.dll.
2 documented commands
Execute T1218.011 System Binary Proxy Execution: Rundll32 User privileges
Launch an executable payload by calling RouteTheCall.
rundll32.exe zipfldr.dll,RouteTheCall {PATH:.exe}IdentifyTrips 1 Sigma rule: mediumPotentially Suspicious Rundll32 Activity by juju4, Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)
Execute T1218.011 System Binary Proxy Execution: Rundll32 User privileges
Launch an executable payload by calling RouteTheCall (obfuscated).
rundll32.exe zipfldr.dll,RouteTheCall file://^C^:^/^W^i^n^d^o^w^s^/^s^y^s^t^e^m^3^2^/^c^a^l^c^.^e^x^eIdentifyTrips 1 Sigma rule: mediumPotentially Suspicious Rundll32 Activity by juju4, Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)
All 2 commands the identifier reads trip a Sigma process-creation rule. These commands and their descriptions are from LOLBAS’s entry for zipfldr.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 zipfldr.dll. 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
Is it the real zipfldr.dll?
C:\Windows\system32\C:\Windows\SysWOW64\2 known copies
10.0.19041.1 (WinBuild.160101.0800) · C:\Windows\SysWOW64\zipfldr.dll · signed by Microsoft Windows
6cc4b493b39999303124d8410bc3f209adf4de96181483a0d28aa806707f43c910.0.19041.1 (WinBuild.160101.0800) · C:\Windows\system32\zipfldr.dll · signed by Microsoft Windows
c771833cab450839f5acadcbdbc42a6f1afa118013d87c6f2adc3c412512bd0aFrom 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.