Alpha2 Alphanumeric Uppercase Encoder - Metasploit
This page contains detailed information about how to use the encoder/x86/alpha_upper metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.
Module Overview
Name: Alpha2 Alphanumeric Uppercase Encoder
Module: encoder/x86/alpha_upper
Source code: modules/encoders/x86/alpha_upper.rb
Disclosure date: -
Last modification time: 2017-07-24 06:26:21 +0000
Supported architecture(s): x86
Supported platform(s): All
Target service / protocol: -
Target network port(s): -
List of CVEs: -
Encodes payloads as alphanumeric uppercase text. This encoder uses SkyLined's Alpha2 encoding suite. A pure alpha encoder is impossible without having a register that points at or near the shellcode. In a default configuration the first few bytes at the beginning are an fnstenv getpc stub (the same as used in shikata_ga_nai) and thus are not alphanumeric. You can set BufferRegister for full alpha (see Encoder options for details).
Module Ranking and Traits
Module Ranking:
- low: The exploit is nearly impossible to exploit (or under 50% success rate) for common platforms. More information about ranking can be found here.
Basic Usage
msf > use encoder/x86/alpha_upper
msf encoder(alpha_upper) > show targets
... a list of targets ...
msf encoder(alpha_upper) > set TARGET target-id
msf encoder(alpha_upper) > show options
... show and set options ...
msf encoder(alpha_upper) > exploit
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Msfconsole Usage
Here is how the encoder/x86/alpha_upper module looks in the msfconsole:
msf6 > use encoder/x86/alpha_upper
msf6 encoder(x86/alpha_upper) > show info
Name: Alpha2 Alphanumeric Uppercase Encoder
Module: encoder/x86/alpha_upper
Platform: All
Arch: x86
Rank: Low
Provided by:
pusscat <[email protected]>
skylined <[email protected]>
Description:
Encodes payloads as alphanumeric uppercase text. This encoder uses
SkyLined's Alpha2 encoding suite. A pure alpha encoder is impossible
without having a register that points at or near the shellcode. In a
default configuration the first few bytes at the beginning are an
fnstenv getpc stub (the same as used in shikata_ga_nai) and thus are
not alphanumeric. You can set BufferRegister for full alpha (see
Encoder options for details).
Module Options
This is a complete list of options available in the encoder/x86/alpha_upper module:
msf6 encoder(x86/alpha_upper) > show options
Module options (encoder/x86/alpha_upper):
Name Current Setting Required Description
---- --------------- -------- -----------
AllowWin32SEH false yes Use SEH to determine the address of the stub (Windows only)
BufferOffset 0 no The offset to the buffer from the start of the register
BufferRegister no The register that points to the encoded payload
Advanced Options
Here is a complete list of advanced options supported by the encoder/x86/alpha_upper module:
msf6 encoder(x86/alpha_upper) > show advanced
Module advanced options (encoder/x86/alpha_upper):
Name Current Setting Required Description
---- --------------- -------- -----------
VERBOSE false no Enable detailed status messages
WORKSPACE no Specify the workspace for this module
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Error Messages
This module may fail with the following error messages:
Check for the possible causes from the code snippets below found in the module source code. This can often times help in identifying the root cause of the problem.
Unable to generate geteip code
Here is a relevant code snippet related to the "Unable to generate geteip code" error message:
52: Rex::Arch::X86::EAX
53: ])
54: else
55: res = Rex::Arch::X86.geteip_fpu(state.badchars, modified_registers)
56: if (not res)
57: raise EncodingError, "Unable to generate geteip code"
58: end
59: buf, reg, off = res
60: end
61: else
62: reg.upcase!
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Related Pull Requests
- #8716 Merged Pull Request: Print_Status -> Print_Good (And OCD bits 'n bobs)
- #8338 Merged Pull Request: Fix msf/core and self.class msftidy warnings
- #8168 Merged Pull Request: change description of alpha encoders
- #6655 Merged Pull Request: use MetasploitModule as a class name
- #6648 Merged Pull Request: Change metasploit class names
- #5510 Merged Pull Request: Fix #4395, support stage encoding with alpha_upper and alpha_mixed
- #5374 Merged Pull Request: Implements msfvenom --smallest
- #2525 Merged Pull Request: Change module boilerplate
- #1241 Merged Pull Request: Removed all $Id$ and $Revision$ occurences
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See Also
Check also the following modules related to this module:
- encoder/x86/add_sub
- encoder/x86/alpha_mixed
- encoder/x86/avoid_underscore_tolower
- encoder/x86/avoid_utf8_tolower
- encoder/x86/bloxor
- encoder/x86/bmp_polyglot
- encoder/x86/call4_dword_xor
- encoder/x86/context_cpuid
- encoder/x86/context_stat
- encoder/x86/context_time
- encoder/x86/countdown
- encoder/x86/fnstenv_mov
- encoder/x86/jmp_call_additive
- encoder/x86/nonalpha
- encoder/x86/nonupper
- encoder/x86/opt_sub
- encoder/x86/service
- encoder/x86/shikata_ga_nai
- encoder/x86/single_static_bit
- encoder/x86/unicode_mixed
- encoder/x86/unicode_upper
- encoder/x86/xor_dynamic
Authors
- pusscat
- skylined
Version
This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.
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