Query: stealth using Dynamic API Resolution
Matching 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)
Near-miss passage: T1027.009 Embedded Payloads. Tactics: stealth. Description: Adversaries may embed payloads within other files to conceal malicious content from defenses. Otherwise seemingly benign files (such as scripts and executables) may be abused to carry and obfuscate malicious payloads and content. In some cases, embedded payloads may also enable adversaries to [Subvert Trust Controls](https://attack.mitre.org/techniques/T1553) by not impacting execution controls such as digital signatures and notarization tickets.(Citation: Sentinel Labs) Adversaries may embed payloads in various file formats to hide payloads.(Citation: Microsoft Learn) This is similar to [Steganography](https://attack.mitre.org/techniques/T1027/003), though does not involve weaving malicious content into specific bytes and patterns related to legitimate digital media formats.(Citation: GitHub PSImage) For example, adversaries have been observed embedding payloads within or as an overlay of an otherwise benign binary.(Citation: Securelist Dtrack2) Adversaries have also been observed nesting payloads (such as executables and run-only scripts) inside a file of the same format.(Citation: SentinelLabs reversing run-only applescripts 2021) Embedded content may also be used as [Process Injection](https://attack.mitre.org/techniques/T1055) payloads used to infect benign system processes.(Citation: Trend Micro) These embedded then injected payloads may be used as part of the modules of malware designed to provide specific features such as encrypting C2 communications in support of an orchestrator module. For example, an embedded module may be injected into default browsers, allowing adversaries to then communicate via the network.(Citation: Malware Analysis Report ComRAT)