Class: Rex::PeScan::Scanner::JmpRegScanner
- Inherits:
-
Generic
- Object
- Generic
- Rex::PeScan::Scanner::JmpRegScanner
show all
- Defined in:
- lib/rex/pescan/scanner.rb
Instance Attribute Summary
Attributes inherited from Generic
#pe, #regex
Instance Method Summary
collapse
Methods inherited from Generic
#initialize, #scan
Instance Method Details
#_build_byte_list(base, regnums) ⇒ Object
build a list for regex of the possible bytes, based on a base byte and a list of register numbers..
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# File 'lib/rex/pescan/scanner.rb', line 89
def _build_byte_list(base, regnums)
regnums.collect { |regnum| Regexp.escape((base | regnum).chr) }.join('')
end
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#_parse_ret(data) ⇒ Object
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# File 'lib/rex/pescan/scanner.rb', line 105
def _parse_ret(data)
if data.length == 1
return "ret"
else
return "retn 0x%04x" % data[1, 2].unpack('v')[0]
end
end
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#_ret_size(section, index) ⇒ Object
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# File 'lib/rex/pescan/scanner.rb', line 93
def _ret_size(section, index)
d = section.read(index, 1)
case d
when "\xc3"
return 1
when "\xc2"
return 3
end
raise RuntimeError, "invalid return opcode"
end
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#config(param) ⇒ Object
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# File 'lib/rex/pescan/scanner.rb', line 68
def config(param)
regnums = param['args']
calls = _build_byte_list(0xd0, regnums - [4]) jmps = _build_byte_list(0xe0, regnums)
pushs1 = _build_byte_list(0x50, regnums)
pushs2 = _build_byte_list(0xf0, regnums)
regexstr = '('
if !calls.empty?
regexstr += "\xff[#{calls}]|"
end
regexstr += "\xff[#{jmps}]|([#{pushs1}]|\xff[#{pushs2}])(\xc3|\xc2..))"
self.regex = Regexp.new(regexstr, nil, 'n')
end
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#scan_section(section, param = {}) ⇒ Object
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# File 'lib/rex/pescan/scanner.rb', line 114
def scan_section(section, param={})
index = 0
hits = [ ]
while (index = section.index(regex, index)) != nil
rva = section.offset_to_rva(index)
message = ''
parse_ret = false
byte1 = section.read(index, 1).unpack("C*")[0]
if byte1 == 0xff
byte2 = section.read(index+1, 1).unpack("C*")[0]
regname = Rex::Arch::X86.reg_name32(byte2 & 0x7)
case byte2 & 0xf8
when 0xd0
message = "call #{regname}"
index += 2
when 0xe0
message = "jmp #{regname}"
index += 2
when 0xf0
retsize = _ret_size(section, index+2)
message = "push #{regname}; " + _parse_ret(section.read(index+2, retsize))
index += 2 + retsize
else
raise "wtf"
end
else
regname = Rex::Arch::X86.reg_name32(byte1 & 0x7)
retsize = _ret_size(section, index+1)
message = "push #{regname}; " + _parse_ret(section.read(index+1, retsize))
index += 1 + retsize
end
hits << [ rva, message ]
end
return hits
end
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