diff --git a/lib/metasploit/framework/jtr/cracker.rb b/lib/metasploit/framework/jtr/cracker.rb
index f02d85db20..0cad2320fb 100644
--- a/lib/metasploit/framework/jtr/cracker.rb
+++ b/lib/metasploit/framework/jtr/cracker.rb
@@ -56,7 +56,7 @@ module Metasploit
                   numericality: {
                       only_integer:             true,
                       greater_than_or_equal_to: 0
-                  }
+                  }, if: 'max_runtime.present?'
 
         validates :wordlist, :'Metasploit::Framework::File_path' => true, if: 'wordlist.present?'
 
diff --git a/spec/lib/metasploit/framework/jtr/cracker_spec.rb b/spec/lib/metasploit/framework/jtr/cracker_spec.rb
index 784ee44691..4991b1d8de 100644
--- a/spec/lib/metasploit/framework/jtr/cracker_spec.rb
+++ b/spec/lib/metasploit/framework/jtr/cracker_spec.rb
@@ -150,4 +150,94 @@ describe Metasploit::Framework::JtR::Cracker do
       expect(cracker.show_command.last).to eq hash_path
     end
   end
+
+  describe 'validations' do
+    context 'failures' do
+      context 'file_path validators' do
+        before(:each) do
+          expect(File).to receive(:file?).and_return false
+        end
+
+        it 'produces the correct error message for config' do
+          cracker.config = config
+          expect(cracker).to_not be_valid
+          expect(cracker.errors[:config]).to include "is not a valid path to a regular file"
+        end
+
+        it 'produces the correct error message for hash_path' do
+          cracker.hash_path = hash_path
+          expect(cracker).to_not be_valid
+          expect(cracker.errors[:hash_path]).to include "is not a valid path to a regular file"
+        end
+
+        it 'produces the correct error message for pot' do
+          cracker.pot = pot
+          expect(cracker).to_not be_valid
+          expect(cracker.errors[:pot]).to include "is not a valid path to a regular file"
+        end
+
+        it 'produces the correct error message for wordlist' do
+          cracker.wordlist = wordlist
+          expect(cracker).to_not be_valid
+          expect(cracker.errors[:wordlist]).to include "is not a valid path to a regular file"
+        end
+      end
+
+      context 'executable_path validators' do
+        before(:each) do
+          expect(File).to receive(:executable?).and_return false
+        end
+
+        it 'produces the correct error message for john_path' do
+          cracker.john_path = john_path
+          expect(cracker).to_not be_valid
+          expect(cracker.errors[:john_path]).to include "is not a valid path to an executable file"
+        end
+      end
+    end
+
+    context 'successes' do
+      context 'file_path validators' do
+        before(:each) do
+          expect(File).to receive(:file?).and_return true
+        end
+
+        it 'produces no error message for config' do
+          cracker.config = config
+          expect(cracker).to be_valid
+          expect(cracker.errors[:config]).to_not include "is not a valid path to a regular file"
+        end
+
+        it 'produces no error message for hash_path' do
+          cracker.hash_path = hash_path
+          expect(cracker).to be_valid
+          expect(cracker.errors[:hash_path]).to_not include "is not a valid path to a regular file"
+        end
+
+        it 'produces no error message for pot' do
+          cracker.pot = pot
+          expect(cracker).to be_valid
+          expect(cracker.errors[:pot]).to_not include "is not a valid path to a regular file"
+        end
+
+        it 'produces no error message for wordlist' do
+          cracker.wordlist = wordlist
+          expect(cracker).to be_valid
+          expect(cracker.errors[:wordlist]).to_not include "is not a valid path to a regular file"
+        end
+      end
+
+      context 'executable_path validators' do
+        before(:each) do
+          expect(File).to receive(:executable?).and_return true
+        end
+
+        it 'produces no error message for john_path' do
+          cracker.john_path = john_path
+          expect(cracker).to be_valid
+          expect(cracker.errors[:john_path]).to_not include "is not a valid path to an executable file"
+        end
+      end
+    end
+  end
 end
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