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Fix #cd for Powershell Sessions #18021

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merged 2 commits into from
May 25, 2023
Merged

Fix #cd for Powershell Sessions #18021

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afb31b0
Add a function to escaple cmd.exe string literals
zeroSteiner May 23, 2023
ed5d516
Sync the .NET working path for Powershell sessions
zeroSteiner May 23, 2023
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2 changes: 1 addition & 1 deletion lib/msf/core/exploit/remote/smb/client/psexec.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -241,7 +241,7 @@ def execute_command_payload(smbshare)

def execute_command(text, bat, cmd)
# Try and execute the provided command
cmd = cmd.gsub('&', '^&')
cmd = Msf::Post::Windows.escape_cmd_literal(cmd, spaces: false)
execute = "%COMSPEC% /C echo #{cmd} ^> %SYSTEMDRIVE%#{text} > #{bat} & %COMSPEC% /C start %COMSPEC% /C #{bat}"
vprint_status("Executing the command: #{execute}")
begin
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2 changes: 1 addition & 1 deletion lib/msf/core/post/file.rb
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Expand Up @@ -49,7 +49,7 @@ def cd(path)
if session.type == 'meterpreter'
session.fs.dir.chdir(e_path)
elsif session.type == 'powershell'
cmd_exec("Set-Location -Path \"#{e_path}\"")
cmd_exec("Set-Location -Path \"#{e_path}\";[System.IO.Directory]::SetCurrentDirectory($(Get-Location))")
else
session.shell_command_token("cd \"#{e_path}\"")
end
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14 changes: 14 additions & 0 deletions lib/msf/core/post/windows.rb
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@@ -1,4 +1,18 @@
# -*- coding: binary -*-

module Msf::Post::Windows
# Escape a string literal value to be included as an argument to cmd.exe. The escaped value *should not* be placed
# within double quotes as this will alter now it is evaluated (e.g. `echo "^"((^&test) Foo^""` is different than
# `echo ^"((^&test) Foo^"`.
#
# @param [String] string The string to escape for use with cmd.exe.
# @param [Boolean] spaces Whether or not to escape spaces. If the string is being passed to echo, set this to false
# otherwise if it's an argument, set it to true.
# @return [String] The escaped string.
def self.escape_cmd_literal(string, spaces:)
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spaces is optional here because sometimes they need to be escaped, and other times they do not.

This snippet demonstrates the issue. A small Python stub is used to print the arguments then one" "argument is passed to it showing that the space is kept but when passed to echo, the double quotes are kept.

Microsoft Windows [Version 10.0.17763.4377](c) 2018 Microsoft Corporation. All rights reserved.
msflab\smcintyre@DC C:\Users\smcintyre>type args.py
import sys; print(repr(sys.argv))
msflab\smcintyre@DC C:\Users\smcintyre>python args.py one" "argument
['args.py', 'one argument']
msflab\smcintyre@DC C:\Users\smcintyre>echo one" "argument 
one" "argument
msflab\smcintyre@DC C:\Users\smcintyre>

Allowing the user to specify means the escaped value can be used in both contexts. Psexec should not escape spaces because the command is passed to echo.

string = string.dup
%w[ ^ & < > | " ].each { |char| string.gsub!(char, "^#{char}") }
string.gsub!(' ', '" "') if spaces
string
end
end