GetTickCount

Created the Monday 18 March 2019. Updated 3 months, 1 week ago.

This is typical timing function which is used to measure time needed to execute some function/instruction set. If the difference is more than fixed threshold, the process exits.

GetTickCount reads from the KUSER_SHARED_DATA page. This page is mapped read-only into the user mode range of the virtual address and read-write in the kernel range. The system clock tick updates the system time, which is stored directly in this page.

ZwGetTickCount is used the same way as GetTickCount. Using KiGetTickCount is faster than calling ZwGetTickCount, but slightly slower than reading from the KUSER_SHARED_DATA page directly.

Technique Identifiers

U0125 B0001.032

Technique Tag

gettickcount

Code Snippets

Description

Original code available here: https://anti-debug.checkpoint.com/techniques/timing.html#kernel-timing

bool IsDebugged(DWORD dwNativeElapsed)
{
    DWORD dwStart = GetTickCount();
    // ... some work
    return (GetTickCount() - dwStart) > dwNativeElapsed;
}

Detection Rules

                                    rule:
  meta:
    name: check for time delay via GetTickCount
    namespace: anti-analysis/anti-debugging/debugger-detection
    author: michael.hunhoff@fireeye.com
    scope: function
    mbc:
      - Anti-Behavioral Analysis::Debugger Detection::Timing/Delay Check GetTickCount [B0001.032]
    examples:
      - Practical Malware Analysis Lab 16-03.exe_:0x4013d0
  features:
    - and:
      - count(api(kernel32.GetTickCount)): 2 or more

Contributors

Additional Resources

External Links

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