Class: Rex::Encoder::Alpha2::AlphaUpper
- Defined in:
- lib/rex/encoder/alpha2/alpha_upper.rb
Class Method Summary collapse
- .default_accepted_chars ⇒ Object
-
.gen_decoder(reg, offset, modified_registers = []) ⇒ String
Generates the decoder stub.
-
.gen_decoder_prefix(reg, offset, modified_registers = []) ⇒ String
Generates the decoder stub prefix.
Methods inherited from Generic
add_terminator, encode, encode_byte, gen_second
Class Method Details
.default_accepted_chars ⇒ Object
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# File 'lib/rex/encoder/alpha2/alpha_upper.rb', line 10 def self.default_accepted_chars ; ('B' .. 'Z').to_a + ('0' .. '9').to_a ; end |
.gen_decoder(reg, offset, modified_registers = []) ⇒ String
Generates the decoder stub
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# File 'lib/rex/encoder/alpha2/alpha_upper.rb', line 92 def self.gen_decoder(reg, offset, modified_registers = []) mod_registers = [] decoder = gen_decoder_prefix(reg, offset, mod_registers) + "V" + # push esi "T" + # push esp "X" + # pop eax "30" + # xor esi, [eax] "V" + # push esi "X" + # pop eax "4A" + # xor al, 41 "P" + # push eax "0A3" + # xor [ecx+33], al "H" + # dec eax "H" + # dec eax "0A0" + # xor [ecx+30], al "0AB" + # xor [ecx+42], al "A" + # inc ecx <--------------- "A" + # inc ecx | "B" + # inc edx | "TAAQ" + # imul eax, [ecx+41], 10 * | "2AB" + # xor al [ecx+42] | "2BB" + # xor al, [edx+42] | "0BB" + # xor [edx+42], al | "X" + # pop eax | "P" + # push eax | "8AC" + # cmp [ecx+43], al | "JJ" + # jnz * -------------------- "I" # first encoded char, fixes the above J mod_registers.concat( [ Rex::Arch::X86::ESP, Rex::Arch::X86::EAX, Rex::Arch::X86::ESI, Rex::Arch::X86::ECX, Rex::Arch::X86::EDX ]) mod_registers.uniq! modified_registers.concat(mod_registers) return decoder end |
.gen_decoder_prefix(reg, offset, modified_registers = []) ⇒ String
Generates the decoder stub prefix
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# File 'lib/rex/encoder/alpha2/alpha_upper.rb', line 18 def self.gen_decoder_prefix(reg, offset, modified_registers = []) if offset > 20 raise 'Critical: Offset is greater than 20' end mod_registers = [] nop_regs = [] mod_regs = [] edx_regs = [] # use inc ebx as a nop here so we still pad correctly if (offset <= 10) nop = 'C' * offset nop_regs.push(Rex::Arch::X86::EBX) unless nop.empty? mod = 'I' * (10 - offset) + nop + 'QZ' # dec ecx,,, push ecx, pop edx mod_regs.push(Rex::Arch::X86::ECX) unless offset == 10 mod_regs.concat(nop_regs) mod_regs.push(Rex::Arch::X86::EDX) edxmod = 'J' * (11 - offset) edx_regs.push(Rex::Arch::X86::EDX) unless edxmod.empty? else mod = 'A' * (offset - 10) mod_regs.push(Rex::Arch::X86::ECX) unless mod.empty? nop = 'C' * (10 - mod.length) nop_regs.push(Rex::Arch::X86::EBX) unless nop.empty? mod << nop + 'QZ' mod_regs.concat(nop_regs) mod_regs.push(Rex::Arch::X86::EDX) edxmod = 'B' * (11 - (offset - 10)) edx_regs.push(Rex::Arch::X86::EDX) unless edxmod.empty? end regprefix = { 'EAX' => 'PY' + mod, # push eax, pop ecx 'ECX' => 'I' + mod, # dec ecx 'EDX' => edxmod + nop + 'RY', # mod edx,,, push edx, pop ecx 'EBX' => 'SY' + mod, # push ebx, pop ecx 'ESP' => 'TY' + mod, # push esp, pop ecx 'EBP' => 'UY' + mod, # push ebp, pop ecx 'ESI' => 'VY' + mod, # push esi, pop ecx 'EDI' => 'WY' + mod, # push edi, pop ecx } reg.upcase! unless regprefix.keys.include?(reg) raise ArgumentError.new("Invalid register name") end case reg when 'EDX' mod_registers.concat(edx_regs) mod_registers.concat(nop_regs) mod_registers.push(Rex::Arch::X86::ECX) else mod_registers.push(Rex::Arch::X86::ECX) mod_registers.concat(mod_regs) end mod_registers.uniq! modified_registers.concat(mod_registers) return regprefix[reg] end |