Injection Utilizing APC (Autonomic Peripheral Component) Technology
APC Process Injection: A Stealthy Method for Malicious Code Execution
Overview
Asynchronous Procedure Call (APC) injection is a cunning technique employed by attackers to execute malicious code within a legitimate process, bypassing security measures that would otherwise prevent unauthorized code execution.
The APC Injection Process
This covert snippet utilizes the GetModuleFileNameA function to retrieve the executable path of the running process. It then checks if the classic anti-analysis trick "explorer.exe " appears in the file. If discovered, the environment is trusted. Otherwise, the code proceeds accordingly.
To enumerate all running processes, the code uses followed by and . It identifies and parses the executable name of each process, comparing it to . If there's a match, the process ID (PID) of explorer.exe is extracted and utilized.
The code then targets explorer.exe and conducts DLL injection. The DLL path is stored using by allocating memory in the target process' address space. Thread IDs are opened using to facilitate a call to using , effectively scheduling the DLL's loading into the target process. This indirect method ensures stealthy arbitrary code execution without direct execution.
APC Injection Techniques
This PowerShell code allocates memory intrinsically and performs APC-based code injection, utilizing virtualAllocEx and copying malicious code. A current thread is opened via , and an asynchronous procedure call (APC) is queued using in an alertable state, allowing the malicious code to execute.
An Example: ISFB APC Process Injection
The following example illustrates APC injection:
- Obtain a Process Handle:
- Copy Shellcode to Target Process (Optional): This step can be bypassed by executing code directly, as APC injection doesn't require explicit memory allocation and writing.
- Queue the APC:
- Important note: should denote the malicious code intended for execution.
- Trigger Execution: The malicious code will be executed once the thread enters an alertable state.
Conclusion
APC process injection offers attackers a stealthy method to execute malicious code within legitimate processes, bypassing traditional security measures. Understanding this technique is vital for developing effective countermeasures against such attacks.
Technology like APC (Asynchronous Procedure Call) injection in cybersecurity is a pervasive technique used by attackers to surreptitiously execute malicious code within legitimate processes, bypassing traditional security measures that would otherwise prevent unauthorized code execution. This technique often employs technology such as , , and to enumerate and target specific processes, and employs functions like to execute the malicious code.
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