Query: SIEM correlation: privilege escalation activity consistent with Accessibility Features
Matching passage: T1546.008 Accessibility Features. Tactics: privilege escalation, persistence. Description: Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by accessibility features. Windows contains accessibility features that may be launched with a key combination before a user has logged in (ex: when the user is on the Windows logon screen). An adversary can modify the way these programs are launched to get a command prompt or backdoor without logging in to the system. Two common accessibility programs are <code>C:\Windows\System32\sethc.exe</code>, launched when the shift key is pressed five times and <code>C:\Windows\System32\utilman.exe</code>, launched when the Windows + U key combination is pressed. The sethc.exe program is often referred to as "sticky keys", and has been used by adversaries for unauthenticated access through a remote desktop login screen. (Citation: FireEye Hikit Rootkit) Depending on the version of Windows, an adversary may take advantage of these features in different ways. Common methods used by adversaries include replacing accessibility feature binaries or pointers/references to these binaries in the Registry. In newer versions of Windows, the replaced binary needs to be digitally signed for x64 systems, the binary must reside in <code>%systemdir%\</code>, and it must be protected by Windows File or Resource Protection (WFP/WRP). (Citation: DEFCON2016 Sticky Keys) The [Image File Execution Options Injection](https://attack.mitre.org/techniques/T1546/012) debugger method was likely discovered as a potential workaround because it does not require the corresponding accessibility feature binary to be replaced. For simple binary replacement on Windows XP and later as well as and Windows Server 2003/R2 and later, for example, the program (e.g., <code>C:\Windows\System32\utilman.exe</code>) may be replaced with "cmd.exe" (or another program that provides backdoor access). Subsequently, pressing the appropriate key combination at the login screen while sitting at the keyboard or when connected
Near-miss passage: T1546.001 Change Default File Association. Tactics: privilege escalation, persistence. Description: Adversaries may establish persistence by executing malicious content triggered by a file type association. When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access or by administrators using the built-in assoc utility.(Citation: Microsoft Change Default Programs)(Citation: Microsoft File Handlers)(Citation: Microsoft Assoc Oct 2017) Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened. System file associations are listed under <code>HKEY_CLASSES_ROOT\.[extension]</code>, for example <code>HKEY_CLASSES_ROOT\.txt</code>. The entries point to a handler for that extension located at <code>HKEY_CLASSES_ROOT\\[handler]</code>. The various commands are then listed as subkeys underneath the shell key at <code>HKEY_CLASSES_ROOT\\[handler]\shell\\[action]\command</code>. For example: * <code>HKEY_CLASSES_ROOT\txtfile\shell\open\command</code> * <code>HKEY_CLASSES_ROOT\txtfile\shell\print\command</code> * <code>HKEY_CLASSES_ROOT\txtfile\shell\printto\command</code> The values of the keys listed are commands that are executed when the handler opens the file extension. Adversaries can modify these values to continually execute arbitrary commands.(Citation: TrendMicro TROJ-FAKEAV OCT 2012)