Query: Encoded PowerShell / command-line abuse matching Deobfuscate/Decode Files or Information
Matching passage: T1140 Deobfuscate/Decode Files or Information. Tactics: stealth. Description: Adversaries may use [Obfuscated Files or Information](https://attack.mitre.org/techniques/T1027) to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system. One such example is the use of [certutil](https://attack.mitre.org/software/S0160) to decode a remote access tool portable executable file that has been hidden inside a certificate file.(Citation: Malwarebytes Targeted Attack against Saudi Arabia) Another example is using the Windows <code>copy /b</code> or <code>type</code> command to reassemble binary fragments into a malicious payload.(Citation: Carbon Black Obfuscation Sept 2016)(Citation: Sentinel One Tainted Love 2023) Sometimes a user's action may be required to open it for deobfuscation or decryption as part of [User Execution](https://attack.mitre.org/techniques/T1204). The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary.(Citation: Volexity PowerDuke November 2016)
Near-miss passage: T1027.007 Dynamic API Resolution. Tactics: stealth. Description: Adversaries may obfuscate then dynamically resolve API functions called by their malware in order to conceal malicious functionalities and impair defensive analysis. Malware commonly uses various [Native API](https://attack.mitre.org/techniques/T1106) functions provided by the OS to perform various tasks such as those involving processes, files, and other system artifacts. API functions called by malware may leave static artifacts such as strings in payload files. Defensive analysts may also uncover which functions a binary file may execute via an import address table (IAT) or other structures that help dynamically link calling code to the shared modules that provide functions.(Citation: Huntress API Hash)(Citation: IRED API Hashing) To avoid static or other defensive analysis, adversaries may use dynamic API resolution to conceal malware characteristics and functionalities. Similar to [Software Packing](https://attack.mitre.org/techniques/T1027/002), dynamic API resolution may change file signatures and obfuscate malicious API function calls until they are resolved and invoked during runtime. Various methods may be used to obfuscate malware calls to API functions. For example, hashes of function names are commonly stored in malware in lieu of literal strings. Malware can use these hashes (or other identifiers) to manually reproduce the linking and loading process using functions such as `GetProcAddress()` and `LoadLibrary()`. These hashes/identifiers can also be further obfuscated using encryption or other string manipulation tricks (requiring various forms of [Deobfuscate/Decode Files or Information](https://attack.mitre.org/techniques/T1140) during execution).(Citation: BlackHat API Packers)(Citation: Drakonia HInvoke)(Citation: Huntress API Hash)