Thread: Memory Editing

  1. #1
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    Exclamation Memory Editing

    I'm making a program that needs to access the memory, etc.. of target programs. Virii and spyware often have a lot of read/write/terminate protection, and that's where I need help. My program gives itself debug rights, but some programs still don't allow PROCESS_VM_WRITE or PROCESS_TERMINATE.

    How do these programs keep me from writing or terminating, even though I've given myself access? And how can I overcome this?

    Here are my active functions:

    In main():
    Code:
    HANDLE hToken;
       if (OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &hToken)) {
          EnablePrivilege(hToken, SE_DEBUG_NAME, TRUE) ;
          CloseHandle(hToken);
          }
    EnablePrivilege():
    Code:
    BOOL EnablePrivilege(HANDLE hToken, LPCTSTR szPrivName, 
       BOOL fEnable) {
    
       TOKEN_PRIVILEGES tp;
       tp.PrivilegeCount = 1;
       LookupPrivilegeValue(NULL, szPrivName, &tp.Privileges[0].Luid);
       tp.Privileges[0].Attributes = fEnable ? SE_PRIVILEGE_ENABLED : 0;
       AdjustTokenPrivileges(hToken, FALSE, &tp, sizeof(tp), NULL, NULL);
       return((GetLastError() == ERROR_SUCCESS));
    }
    When set to PROCESS_VM_WRITE or PROCESS_TERMINATE, m_hProcess goes unchanged [NULL]. PROCESS_VM_READ is allowed on all programs, even those that deny access when I don't set permissions. It sets m_hProcess to a handle, like it should.
    Code:
    m_hProcess = ::OpenProcess(PROCESS_VM_READ, false, _PID)
    Last edited by Denethor2000; 11-02-2005 at 02:46 PM.

  2. #2
    Hardware Engineer
    Join Date
    Sep 2001
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    1,398
    This is Windows, right?

    The operating system prevents you from accessing another program's memory, or the operating system's memory space. As far as I know, you can't do this with a user-mode program. So, I think you have to write a kernel-mode (driver) program.

  3. #3
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    Yes this is Windows XP.

    I've read and written memory to multiple programs. Programs related in no way to mine. A few deny me access.

    Could this be a hook they've initialized on the DLL I'm accessing? Either way, would a DLL hook be a solution?

  4. #4
    Bioport Productions
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    Oct 2005
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    I don't know what exactly you're trying to do but have you tried using ReadProcessMemory/WriteProcessMemory ? As far as I know, you don't need an privileges to use them and they work on all windows programs.
    -"What we wish, we readily believe, and what we ourselves think, we imagine others think also."
    PHP Code:
    sadf 

  5. #5
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    Quote Originally Posted by durban
    I don't know what exactly you're trying to do but have you tried using ReadProcessMemory/WriteProcessMemory ? As far as I know, you don't need an privileges to use them and they work on all windows programs.
    Can't WriteProcessMemory or ReadProcessMemory without the correct handle.

    For example.
    This grabs the ReadProcessMemory handle:
    Code:
    m_hProcess = ::OpenProcess(PROCESS_VM_READ, false, _PID)

    This grabs the WriteProcessMemory handle:
    Code:
    m_hProcess = ::OpenProcess(PROCESS_VM_WRITE, false, _PID)
    My access to the handle is denied with PROCESS_VM_WRITE. And I can't write anything without the handle.

  6. #6
    Bioport Productions
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    Hmm, try using PROCESS_ALL_ACCESS.
    -"What we wish, we readily believe, and what we ourselves think, we imagine others think also."
    PHP Code:
    sadf 

  7. #7
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    I don't have access to any but _READ

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