134 lines
2.6 KiB
Ruby
134 lines
2.6 KiB
Ruby
# This file is part of Metasm, the Ruby assembly manipulation suite
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# Copyright (C) 2007 Yoann GUILLOT
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#
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# Licence is LGPL, see LICENCE in the top-level directory
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# here we compile and inject a C stub into a running process
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# the sample stub will scan the whole process memory for a 32bit value (aligned)
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# and report the results using MessageBox
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#
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# This shows how to mix C and asm, and a few WinOS functions.
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require 'metasm'
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include Metasm
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abort 'usage: scan <targetprocess> <value>' if ARGV.length != 2
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targetproc = ARGV.shift
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searchval = Integer(ARGV.shift)
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raise 'cannot find target' if not target = WinOS.find_process(targetproc)
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sc = Shellcode.compile_c(Ia32.new, <<'EOC')
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asm {
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sc_start:
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xor edi, edi
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mov ebp, edi // ebp = match count
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push fs:[edi] // backup UEH
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call setup_ueh
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// our UEH: edi += 4k, check for end of addrspace
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ueh:
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mov eax, [esp+0ch]
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add eax, 7ch // optimize code size
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add dword ptr [eax+21h], 10h // ctx[edi] += 4k
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cmp word ptr [eax+22h], -1
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jb ueh_retloc
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call ueh_endloop // ctx[eip] = &jmp walk_loop_end
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jmp walk_loop_end
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ueh_endloop:
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pop dword ptr [eax+3ch]
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ueh_retloc:
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xor eax, eax
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ret // UEH: return(CONTINUE)
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// end of UEH
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setup_ueh:
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push -1
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mov fs:[edi], esp
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mov eax, SEARCHEDVALUE
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walk_loop_next:
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cmp edi, 0xffff_fff0
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jae walk_loop_end
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scasd
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jnz walk_loop_next
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found:
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call found_value
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jmp walk_loop_next
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walk_loop_end:
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pop eax
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pop ebx
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inc eax
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pop dword ptr fs:[eax]
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call metasm_intern_geteip
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mov [eax+matchcount-metasm_intern_geteip], ebp
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call scan_finished
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// virtualfree shellcode & exitthread
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push 8000h // type = MEM_RELEASE
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push 0 // size = 0
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call end_getaddr // addr = sc_start
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end_getaddr:
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add dword ptr [esp], end_getaddr - sc_start
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push ExitThread
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jmp VirtualFree
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// end of main
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// found new match at edi
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found_value:
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push eax
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cmp ebp, 1024
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jae skipsave
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call metasm_intern_geteip
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add eax, table - metasm_intern_geteip
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sub edi, 4
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mov dword ptr [eax+4*ebp], edi
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add edi, 4
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inc ebp
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skipsave:
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pop eax
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mov dword ptr [esp-4], 0 // hide the searched value from our stack
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ret
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}
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__declspec(stdcall) void MessageBoxA(int, char*, char*, int);
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int wsprintfA(char *buf, char *fmt, ...);
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unsigned long table[1024];
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unsigned long matchcount;
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char outbuf[4096];
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void scan_finished(void)
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{
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int off = 0;
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int i;
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off += wsprintfA(outbuf+off, "Found %d matches: ", matchcount);
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for (i=0 ; i<matchcount ; i++) {
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if (off > sizeof(outbuf)-20)
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break;
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off += wsprintfA(outbuf+off, "%X, ", table[i]);
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}
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outbuf[off-2] = '.';
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outbuf[off-1] = 0;
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MessageBoxA(0, outbuf, "search finished", 0);
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}
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EOC
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sc = sc.encoded
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sc.fixup! 'SEARCHEDVALUE' => searchval
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WinOS.inject_run_shellcode(target, sc)
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