Query: how to detect Application Shimming
Matching passage: T1546.011 Application Shimming. Tactics: privilege escalation, persistence. Description: Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by application shims. The Microsoft Windows Application Compatibility Infrastructure/Framework (Application Shim) was created to allow for backward compatibility of software as the operating system codebase changes over time. For example, the application shimming feature allows developers to apply fixes to applications (without rewriting code) that were created for Windows XP so that it will work with Windows 10. (Citation: Elastic Process Injection July 2017) Within the framework, shims are created to act as a buffer between the program (or more specifically, the Import Address Table) and the Windows OS. When a program is executed, the shim cache is referenced to determine if the program requires the use of the shim database (.sdb). If so, the shim database uses hooking to redirect the code as necessary in order to communicate with the OS. A list of all shims currently installed by the default Windows installer (sdbinst.exe) is kept in: * <code>%WINDIR%\AppPatch\sysmain.sdb</code> and * <code>hklm\software\microsoft\windows nt\currentversion\appcompatflags\installedsdb</code> Custom databases are stored in: * <code>%WINDIR%\AppPatch\custom & %WINDIR%\AppPatch\AppPatch64\Custom</code> and * <code>hklm\software\microsoft\windows nt\currentversion\appcompatflags\custom</code> To keep shims secure, Windows designed them to run in user mode so they cannot modify the kernel and you must have administrator privileges to install a shim. However, certain shims can be used to [Bypass User Account Control](https://attack.mitre.org/techniques/T1548/002) (UAC and RedirectEXE), inject DLLs into processes (InjectDLL), disable Data Execution Prevention (DisableNX) and Structure Exception Handling (DisableSEH), and intercept memory addresses (GetProcAddress). Utilizing these shims may allow an adversary to perform several malicious acts such as elevate privileges, install backdo
Near-miss passage: T1546.012 Image File Execution Options Injection. Tactics: privilege escalation, persistence. Description: Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by Image File Execution Options (IFEO) debuggers. IFEOs enable a developer to attach a debugger to an application. When a process is created, a debugger present in an application’s IFEO will be prepended to the application’s name, effectively launching the new process under the debugger (e.g., <code>C:\dbg\ntsd.exe -g notepad.exe</code>).(Citation: Microsoft Dev Blog IFEO Mar 2010) IFEOs can be set directly via the Registry or in Global Flags via the GFlags tool.(Citation: Microsoft GFlags Mar 2017) IFEOs are represented as <code>Debugger</code> values in the Registry under <code>HKLM\SOFTWARE{\Wow6432Node}\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\<executable></code> where <code>&lt;executable&gt;</code> is the binary on which the debugger is attached.(Citation: Microsoft Dev Blog IFEO Mar 2010) IFEOs can also enable an arbitrary monitor program to be launched when a specified program silently exits (i.e. is prematurely terminated by itself or a second, non kernel-mode process).(Citation: Microsoft Silent Process Exit NOV 2017)(Citation: Oddvar Moe IFEO APR 2018) Similar to debuggers, silent exit monitoring can be enabled through GFlags and/or by directly modifying IFEO and silent process exit Registry values in <code>HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\</code>.(Citation: Microsoft Silent Process Exit NOV 2017)(Citation: Oddvar Moe IFEO APR 2018) Similar to [Accessibility Features](https://attack.mitre.org/techniques/T1546/008), on Windows Vista and later as well as Windows Server 2008 and later, a Registry key may be modified that configures "cmd.exe," or another program that provides backdoor access, as a "debugger" for an accessibility program (ex: utilman.exe). After the Registry is modified, pressing the appropriate key combination at the login screen while at the keyboard or when connecte