Move crypto methods to Rex::Crypto namespace

lib/msf/base/simple/buffer.rb

@@ -146,7 +146,7 @@ module Buffer
         raise ArgumentError, 'Encryption key is missing'
       end
 
-      buf = Rex::Text.encrypt_aes256(encryption_opts[:iv], encryption_opts[:key], value)
+      buf = Rex::Crypto.encrypt_aes256(encryption_opts[:iv], encryption_opts[:key], value)
     when 'base64'
       buf = Rex::Text.encode_base64(value)
     when 'xor'
@@ -160,7 +160,7 @@ module Buffer
         raise ArgumentError, 'Encryption key is missing'
       end
 
-      buf = Rex::Text.rc4(encryption_opts[:key], value)
+      buf = Rex::Crypto.rc4(encryption_opts[:key], value)
     else
       raise ArgumentError, "Unsupported encryption format: #{encryption_opts[:format]}", caller
     end

lib/rex.rb

@@ -114,6 +114,10 @@ require 'rex/compat'
 require 'rex/sslscan/scanner'
 require 'rex/sslscan/result'
 
+# Cryptography
+require 'rex/crypto/aes256'
+require 'rex/crypto/rc4'
+
 
 # Overload the Kernel.sleep() function to be thread-safe
 Kernel.class_eval("

lib/rex/crypto/aes256.rb

@@ -0,0 +1,33 @@
+# -*- coding: binary -*-
+
+module Rex
+  module Crypto
+
+    # Returns an encrypted string using AES256-CBC.
+    #
+    # @param iv [String] Initialization vector.
+    # @param key [String] Secret key.
+    # @return [String] The encrypted string.
+    def self.encrypt_aes256(iv, key, value)
+      aes = OpenSSL::Cipher::AES256.new(:CBC)
+      aes.encrypt
+      aes.iv = iv
+      aes.key = key
+      aes.update(value) + aes.final
+    end
+
+    # Returns a decrypted string using AES256-CBC.
+    #
+    # @param iv [String] Initialization vector.
+    # @param key [String] Secret key.
+    # @return [String] The decrypted string.
+    def self.decrypt_aes256(iv, key, value)
+      aes = OpenSSL::Cipher::AES256.new(:CBC)
+      aes.decrypt
+      aes.iv = iv
+      aes.key = key
+      aes.update(value) + aes.final
+    end
+
+  end
+end

lib/rex/crypto/rc4.rb

@@ -0,0 +1,18 @@
+# -*- coding: binary -*-
+
+module Rex
+  module Crypto
+
+    # Returns a decrypted or encrypted RC4 string.
+    #
+    # @param key [String] Secret key.
+    # @param [String]
+    def self.rc4(key, value)
+      rc4 = RC4.new(key)
+
+      # This can also be used to decrypt
+      rc4.encrypt(value)
+    end
+
+  end
+end

spec/lib/rex/crypto/aes256_spec.rb

@@ -0,0 +1,62 @@
+require 'spec_helper'
+require 'securerandom'
+
+
+describe Rex::Crypto do
+
+    let(:iv) {
+      SecureRandom.random_bytes(16)
+    }
+
+    let(:key) {
+      SecureRandom.random_bytes(32)
+    }
+
+    let(:value) {
+      'Hello World'
+    }
+
+  describe '#encrypt_aes256' do
+    it 'raises an exception due to a short IV' do
+      iv = SecureRandom.random_bytes(1)
+      # Because it could raise either a OpenSSL::Cipher::CipherError or an ArgumentError
+      # dependong on the environment, we will just expect it to raise an exception
+      expect { Rex::Crypto.encrypt_aes256(iv, key, value) }.to raise_exception
+    end
+
+    it 'raises an exception due to a short key' do
+      key = SecureRandom.random_bytes(1)
+      # Because it could raise either a OpenSSL::Cipher::CipherError or an ArgumentError
+      # dependong on the environment, we will just expect it to raise an exception
+      expect { Rex::Crypto.encrypt_aes256(iv, key, value) }.to raise_exception
+    end
+
+    it 'encrypts the string Hello World' do
+      encrypted_str = Rex::Crypto.encrypt_aes256(iv, key, value)
+      expect(encrypted_str).not_to eq(value)
+    end
+  end
+
+  describe '#decrypt_aes256' do
+    it 'raises an exception due to a short IV' do
+      iv = SecureRandom.random_bytes(1)
+      # Because it could raise either a OpenSSL::Cipher::CipherError or an ArgumentError
+      # dependong on the environment, we will just expect it to raise an exception
+      expect { Rex::Crypto.decrypt_aes256(iv, key, value) }.to raise_exception
+    end
+
+    it 'raises an exception due to a short key' do
+      key = SecureRandom.random_bytes(1)
+      # Because it could raise either a OpenSSL::Cipher::CipherError or an ArgumentError
+      # dependong on the environment, we will just expect it to raise an exception
+      expect { Rex::Crypto.decrypt_aes256(iv, key, value) }.to raise_exception
+    end
+
+    it 'decrypts the value to Hello World' do
+      encrypted_str = Rex::Crypto.encrypt_aes256(iv, key, value)
+      decrypted_str = Rex::Crypto.decrypt_aes256(iv, key, encrypted_str)
+      expect(decrypted_str).to eq(value)
+    end
+  end
+
+end

spec/lib/rex/crypto/rc4_spec.rb

@@ -0,0 +1,28 @@
+require 'spec_helper'
+require 'securerandom'
+
+
+describe Rex::Crypto do
+
+  describe '#rc4' do
+
+    let(:key) {
+      SecureRandom.random_bytes(32)
+    }
+
+    let(:value) {
+      'Hello World'
+    }
+
+    it 'encrypts a string' do
+      expect(Rex::Crypto.rc4(key, value)).not_to eq(value)
+    end
+
+    it 'decrypts a string' do
+      encrypted_str = Rex::Crypto.rc4(key, value)
+      decrypted_str = Rex::Crypto.rc4(key, encrypted_str)
+      expect(decrypted_str).to eq(value)
+    end
+
+  end
+end