Adversaries may hook into application programming interface (API) functions used by processes to redirect calls for execution and privilege escalation means. Windows processes often leverage these API functions to perform tasks that require reusable system resources. Windows API functions are typically stored in dynamic-link libraries (DLLs) as exported functions. [1]

One type of hooking seen in ICS involves redirecting calls to these functions via import address table (IAT) hooking. IAT hooking uses modifications to a processs IAT, where pointers to imported API functions are stored. [2]

ID: T0874
Sub-techniques:  No sub-techniques
Platforms: Engineering Workstation
Version: 1.1
Created: 21 May 2020
Last Modified: 27 September 2022

Procedure Examples

ID Name Description
S0603 Stuxnet

Stuxnet modifies the Import Address Tables DLLs to hook specific APIs that are used to open project files. [2]

S1009 Triton

Triton's injector, inject.bin, changes the function pointer of the 'get main processor diagnostic data' TriStation command to the address of imain.bin so that it is executed prior to the normal handler. [3]


ID Mitigation Description
M0947 Audit

Perform audits or scans of systems, permissions, insecure software, insecure configurations, etc. to identify potential weaknesses. Perform periodic integrity checks of the device to validate the correctness of the firmware, software, programs, and configurations. Integrity checks, which typically include cryptographic hashes or digital signatures, should be compared to those obtained at known valid states, especially after events like device reboots, program downloads, or program restarts.

M0944 Restrict Library Loading

Restrict the use of untrusted or unknown libraries, such as remote or unknown DLLs.


ID Data Source Data Component Detects
DS0009 Process OS API Execution

Monitor for API calls that can be used to install a hook procedure, such as the SetWindowsHookEx and SetWinEventHook functions.[4][5] Also consider analyzing hook chains (which hold pointers to hook procedures for each type of hook) using tools[5][6][7] or by programmatically examining internal kernel structures.[8][9]

Process Metadata

Verify integrity of live processes by comparing code in memory to that of corresponding static binaries, specifically checking for jumps and other instructions that redirect code flow.