EventPairHandles

Created the Monday 18 March 2019. Updated 3 years, 10 months ago.

An EventPair Object is an event constructed by two _KEVENT structures which are conventionally named High and Low.

There is a relation between generic Event Objects and Debuggers because they must create a custom event called DebugEvent able to handle exceptions. Due to the presence of events owned by the Debugger, every information relative to the events of a normal process differs from a debugged process.

Technique Identifier

U0116

Technique Tag

EventPairHandles

Code Snippets

#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <iostream>
#include <stdlib.h>
#include <windows.h>
#include "defs.h"


#pragma comment(lib,"ntdll.lib")
#pragma comment(lib,"psapi.lib")


void QueryProcessHeapMethod(void)
{
    PDEBUG_BUFFER buffer;
    buffer = RtlCreateQueryDebugBuffer(0,FALSE);
    RtlQueryProcessHeapInformation(buffer);

    if (buffer->RemoteSectionBase == (PVOID) 0x50000062){
        MessageBoxA(NULL,"Debugged","Warning",MB_OK);
    }
    else {
        MessageBoxA(NULL,"Not Debugged","Warning",MB_OK);
    }
    if (buffer->EventPairHandle == (PVOID) 0x00002b98) {
        MessageBoxA(NULL,"Debugged","Warning",MB_OK);
    }
    else {
        MessageBoxA(NULL,"Not Debugged","Warning",MB_OK);
        printf("EventPairHandle= %x",(int)buffer->EventPairHandle);
    }
}
int main()
{
    QueryProcessHeapMethod();
    return (EXIT_SUCCESS);
}

Detection Rules

                                    rule Detect_EventPairHandles: AntiDebug {
    meta: 
        description = "Detect EventPairHandlesas anti-debug"
        author = "Unprotect"
        comment = "Experimental rule"
    strings:
        $1 = "EventPairHandles" fullword ascii
        $2 = "RtlCreateQueryDebugBuffer" fullword ascii
        $3 = "RtlQueryProcessHeapInformation" fullword ascii
    condition:   
       uint16(0) == 0x5A4D and filesize < 1000KB and 2 of them 
}

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.

https://www.evilfingers.com/publications/research_EN/EventPairsHandle.pdf