Applied Cybernetics Group
T1027.007 Dynamic API Resolution
coverage gap
- Technique
T1027.007- Tactics
- Defense Evasion
- Research, 90 days
- 1
- KEV CVEs mapped
- 0
- SigmaHQ rules
- 0
- Elastic, Splunk
- 0
- thrunt rules
- 0
- Upstream
- https://attack.mitre.org/techniques/T1027/007
MITRE 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)
Research citing this technique
Reports and advisories from the last 90 days that cite this technique.
Detection coverage
No rule covers this technique yet. No SigmaHQ, Elastic or Splunk production rule carries its tag, and thrunt hasn't written one. Techniques like this are where the next thrunt rules come from; the gap map has the full list.