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Get Started Free →cyberstrikeus/T1027.007_dynamic-api-resolution
Adversaries may obfuscate then dynamically resolve API functions called by their malware in order to conceal malicious functionalities and impair defensive analysis.
Passed 17 of 19 test cases with the skill, and 10 of 19 without it.
and 7 more in the full report
9 fixed11 passed either way2 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.
In the PowerShell execution script for the Ninja-syscall atomic test, how many seconds does the script pause to allow process completion before validating and cleaning up the log artifact?
| Checked | Without skill | With skill |
|---|---|---|
| Specifies a pause duration of 7 seconds in the script. | Missed | Passed |
The instructions your model reads when the skill loads.
Sub-technique of: T1027
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 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.
To avoid static or other defensive analysis, adversaries may use dynamic API resolution to conceal malware characteristics and functionalities. Similar to Software Packing, 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 during execution).
Platforms: Windows
The following tests are from Atomic Red Team and provide actionable ways to test this technique:
This test calls NtCreateFile via API hashing and dynamic syscall resolution. I have dubbed this particular combination of techniques 'Ninja-syscall'. When successful, a new file named 'hello.log' will be created in the default user's temporary folder, which is a common location for a dropper.
Supported Platforms: windows Elevation Required: Yes
test cases passed, vs 10 / 19 without
More skills from the same source and nearby in the registry, with their headline benchmark lift.