Identifier / Programs / Windows
url.dll
Internet Shortcut Shell Extension DLL file version info (xCyclopedia)
LOLBAS Execute 1 ATT&CK technique 6 documented commands 2 known copies with hashes
How url.dll is abused
Execute T1218.011 System Binary Proxy Execution: Rundll32
Run by rundll32.exe: url.dll,openurl
Execute T1218.011 System Binary Proxy Execution: Rundll32
Run by rundll32.exe: url.dll,fileprotocolhandler
Each abuse is LOLBAS's category and the options and words it uses; the full write-up is on LOLBAS's page for url.dll.
6 documented commands
Execute T1218.011 System Binary Proxy Execution: Rundll32 User privileges
Launch a HTML application payload by calling OpenURL.
rundll32.exe url.dll,OpenURL {PATH_ABSOLUTE:.hta}Trips 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 via proxy through a .url (information) file by calling OpenURL.
rundll32.exe url.dll,OpenURL {PATH_ABSOLUTE:.url}Trips 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 by calling OpenURL.
rundll32.exe url.dll,OpenURL file://^C^:^/^W^i^n^d^o^w^s^/^s^y^s^t^e^m^3^2^/^c^a^l^c^.^e^x^eTrips 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 by calling FileProtocolHandler.
rundll32.exe url.dll,FileProtocolHandler {PATH_ABSOLUTE:.exe}Trips 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 by calling FileProtocolHandler.
rundll32.exe url.dll,FileProtocolHandler file://^C^:^/^W^i^n^d^o^w^s^/^s^y^s^t^e^m^3^2^/^c^a^l^c^.^e^x^eTrips 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 a HTML application payload by calling FileProtocolHandler.
rundll32.exe url.dll,FileProtocolHandler file:///C:/test/test.htaTrips 1 Sigma rule: mediumPotentially Suspicious Rundll32 Activity by juju4, Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)
All 6 commands the identifier reads trip a Sigma process-creation rule. These commands and their descriptions are from LOLBAS’s entry for url.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 url.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 url.dll?
C:\Windows\system32\C:\Windows\SysWOW64\2 known copies
11.00.19041.1 (WinBuild.160101.0800) · C:\Windows\system32\url.dll · signed by Microsoft Windows
36bb3d6893068ff80cf83772447849f8d2df551280c9ee532e793518e5cf62b511.00.19041.1 (WinBuild.160101.0800) · C:\Windows\SysWOW64\url.dll · signed by Microsoft Windows
cc85a7b90afbbf967c99f7cb1737e9ad0c7924b03859e4d569c903e2d403a24cFrom 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.