Adversaries may abuse the KernelCallbackTable of a process to hijack its execution flow in order to run their own payloads.(Citation: Lazarus APT January 2022)(Citation: FinFisher exposed ) The KernelCallbackTable can be found in the Process Environment Block (PEB) and is initialized to an array of graphic functions available to a GUI process once user32.dll is loaded.(Citation: Windows Process Injection KernelCallbackTable) An adversary may hijack the execution flow of a process using the KernelCallbackTable by replacing an original callback function with a malicious payload. Modifying callback functions can be achieved in various ways involving related behaviors such as [Reflective Code Loading](https://attack.mitre.org/techniques/T1620) or [Process Injection](https://attack.mitre.org/techniques/T1055) into another process. A pointer to the memory address of the KernelCallbackTable can be obtained by locating the PEB (ex: via a call to the NtQueryInformationProcess() [Native API](https://attack.mitre.org/techniques/T1106) function).(Citation: NtQueryInformationProcess) Once the pointer is located, the KernelCallbackTable can be duplicated, and a function in the table (e.g., fnCOPYDATA) set to the address of a malicious payload (ex: via WriteProcessMemory()). The PEB is then updated with the new address of the table. Once the tampered function is invoked, the malicious payload will be triggered.(Citation: Lazarus APT January 2022) The tampered function is typically invoked using a Windows message. After the process is hijacked and malicious code is executed, the KernelCallbackTable may also be restored to its original state by the rest of the malicious payload.(Citation: Lazarus APT January 2022) Use of the KernelCallbackTable to hijack execution flow may evade detection from security products since the execution can be masked under a legitimate process.

Linked Issues

Issuelinks
Linktyp Issue
is related to Techniques
is blocked by Detection Strategy for Hijack Execution Flow through the KernelCallbackTable on Windows.
is blocked by Behavior Prevention on Endpoint
is blocked by Security, Compliance & Resilience Controls Oversight
is blocked by Secure Baseline Configurations
is blocked by Continuous Monitoring
is blocked by Malicious Code Protection (Anti-Malware)
is blocked by Endpoint File Integrity Monitoring (FIM)
is blocked by Input Data Validation
is blocked by Software & Firmware Patching
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