From d0d383c8db0fa24aaa657f5605fe43fd45c989b3 Mon Sep 17 00:00:00 2001
From: William Vu <William_Vu@rapid7.com>
Date: Thu, 31 Jan 2019 22:04:29 -0600
Subject: [PATCH 1/2] Move command_exists? to Msf::Post::Common

---
 lib/msf/core/post/common.rb         | 10 +++++++++-
 lib/msf/core/post/linux/system.rb   | 10 ----------
 lib/msf/core/post/solaris/system.rb | 10 ----------
 3 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/lib/msf/core/post/common.rb b/lib/msf/core/post/common.rb
index 47ea697b16..1fdfd1e3bf 100644
--- a/lib/msf/core/post/common.rb
+++ b/lib/msf/core/post/common.rb
@@ -235,6 +235,14 @@ module Msf::Post::Common
     nil
   end
 
-  private
+  #
+  # Checks if the `cmd` is installed on the system
+  # @return [Boolean]
+  #
+  def command_exists?(cmd)
+    cmd_exec("command -v #{cmd} && echo true").to_s.include? 'true'
+  rescue
+    raise "Unable to check if command `#{cmd}' exists"
+  end
 
 end
diff --git a/lib/msf/core/post/linux/system.rb b/lib/msf/core/post/linux/system.rb
index 47c5968667..dd216f574a 100644
--- a/lib/msf/core/post/linux/system.rb
+++ b/lib/msf/core/post/linux/system.rb
@@ -225,16 +225,6 @@ module System
     raise 'Unable to check for gcc'
   end
 
-  #
-  # Checks if the `cmd` is installed on the system
-  # @return [Boolean]
-  #
-  def command_exists?(cmd)
-    cmd_exec("command -v #{cmd} && echo true").to_s.include? 'true'
-  rescue
-    raise "Unable to check if command `#{cmd}` exists"
-  end
-
   #
   # Gets the process id(s) of `program`
   # @return [Array]
diff --git a/lib/msf/core/post/solaris/system.rb b/lib/msf/core/post/solaris/system.rb
index 4e3870c5c9..c6524e776a 100644
--- a/lib/msf/core/post/solaris/system.rb
+++ b/lib/msf/core/post/solaris/system.rb
@@ -118,16 +118,6 @@ module System
     raise 'Unable to check for gcc'
   end
 
-  #
-  # Checks if the `cmd` is installed on the system
-  # @return [Boolean]
-  #
-  def command_exists?(cmd)
-    cmd_exec("command -v #{cmd} && echo true").to_s.include? 'true'
-  rescue
-    raise "Unable to check if command `#{cmd}` exists"
-  end
-
   #
   # Gets the process id(s) of `program`
   # @return [Array]

From 62560f958119d843f4f65325386878f52804820b Mon Sep 17 00:00:00 2001
From: William Vu <William_Vu@rapid7.com>
Date: Thu, 31 Jan 2019 22:07:30 -0600
Subject: [PATCH 2/2] Add rudimentary Windows support to command_exists?

---
 lib/msf/core/post/common.rb | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/msf/core/post/common.rb b/lib/msf/core/post/common.rb
index 1fdfd1e3bf..1ba1c663b3 100644
--- a/lib/msf/core/post/common.rb
+++ b/lib/msf/core/post/common.rb
@@ -240,7 +240,13 @@ module Msf::Post::Common
   # @return [Boolean]
   #
   def command_exists?(cmd)
-    cmd_exec("command -v #{cmd} && echo true").to_s.include? 'true'
+    if session.platform == 'windows'
+      # https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/where_1
+      # https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/if
+      cmd_exec("cmd /c where /q #{cmd} & if not errorlevel 1 echo true").to_s.include? 'true'
+    else
+      cmd_exec("command -v #{cmd} && echo true").to_s.include? 'true'
+    end
   rescue
     raise "Unable to check if command `#{cmd}' exists"
   end