Thread Execution Hijacking

Created the Saturday 23 March 2019. Updated 2 months ago.

Thread execution hijacking is a technique used by malware to evade detection by targeting an existing thread of a process and avoiding any noisy process or thread creation operations. This technique allows the malware to run its code within the context of the targeted thread, without creating new processes or threads, which can be easily detected by security software.

During analysis, it is possible to observe calls to CreateToolhelp32Snapshot and Thread32First functions followed by OpenThread, which are used by the malware to enumerate and select the target thread.

Technique Identifiers

U1223 E1055.003

Technique Tags

thread execution hijacking malware evading detection existing thread process avoiding noisy process thread creations operations analysis CreateToolhelp32Snapshot Thread32First

Featured Windows API's

Below, you will find a list of the most commonly used Windows API's that are currently utilized by malware authors for current evasion technique. This list is meant to provide an overview of the API's that are commonly used for this purpose. If there are any API's that you feel should be included on this list, please do not hesitate to contact us. We will be happy to update the list and provide any additional information or documentation that may be helpful.

Code Snippets

#include <Windows.h>
#include <TlHelp32.h>

int main()
{
    // Create a snapshot of all running threads
    HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);

    if (hSnapshot != INVALID_HANDLE_VALUE)
    {
        THREADENTRY32 te32;
        te32.dwSize = sizeof(THREADENTRY32);

        // Enumerate all running threads
        if (Thread32First(hSnapshot, &te32))
        {
            do
            {
                // Check if the thread belongs to the target process
                if (te32.th32OwnerProcessID == targetProcessId)
                {
                    // Open the thread
                    HANDLE hThread = OpenThread(THREAD_SET_CONTEXT, 0, te32.th32ThreadID);

                    if (hThread != NULL)
                    {
                        // Inject your code here

                        CloseHandle(hThread);
                    }
                }
            } while (Thread32Next(hSnapshot, &te32));
        }

        CloseHandle(hSnapshot);
    }
}

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

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