MFA Sample

Closes gh-7

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/CustomUser.java

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+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * A custom user representation.
+ *
+ * @author Rob Winch
+ */
+public class CustomUser {
+
+	private final long id;
+
+	private final String email;
+
+	@JsonIgnore
+	private final String password;
+
+	@JsonIgnore
+	private final String secret;
+
+	@JsonIgnore
+	private final String answer;
+
+	@JsonCreator
+	public CustomUser(long id, String email, String password, String secret, String answer) {
+		this.id = id;
+		this.email = email;
+		this.password = password;
+		this.secret = secret;
+		this.answer = answer;
+	}
+
+	public CustomUser(CustomUser user) {
+		this(user.id, user.email, user.password, user.secret, user.answer);
+	}
+
+	public long getId() {
+		return this.id;
+	}
+
+	public String getEmail() {
+		return this.email;
+	}
+
+	public String getPassword() {
+		return this.password;
+	}
+
+	public String getSecret() {
+		return this.secret;
+	}
+
+	public String getAnswer() {
+		return this.answer;
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/CustomUserRepository.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+public interface CustomUserRepository {
+
+	CustomUser findCustomUserByEmail(String email);
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/CustomUserRepositoryUserDetailsService.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.AuthorityUtils;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.stereotype.Service;
+
+@Service
+public class CustomUserRepositoryUserDetailsService implements UserDetailsService {
+
+	private final CustomUserRepository userRepository;
+
+	public CustomUserRepositoryUserDetailsService(CustomUserRepository userRepository) {
+		this.userRepository = userRepository;
+	}
+
+	@Override
+	public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
+		CustomUser customUser = this.userRepository.findCustomUserByEmail(username);
+		if (customUser == null) {
+			throw new UsernameNotFoundException("username " + username + " is not found");
+		}
+		return new CustomUserDetails(customUser);
+	}
+
+	static final class CustomUserDetails extends CustomUser implements UserDetails {
+
+		private static final List<GrantedAuthority> ROLE_USER = Collections
+				.unmodifiableList(AuthorityUtils.createAuthorityList("ROLE_USER"));
+
+		CustomUserDetails(CustomUser customUser) {
+			super(customUser);
+		}
+
+		@Override
+		public Collection<? extends GrantedAuthority> getAuthorities() {
+			return ROLE_USER;
+		}
+
+		@Override
+		public String getUsername() {
+			return getEmail();
+		}
+
+		@Override
+		public boolean isAccountNonExpired() {
+			return true;
+		}
+
+		@Override
+		public boolean isAccountNonLocked() {
+			return true;
+		}
+
+		@Override
+		public boolean isCredentialsNonExpired() {
+			return true;
+		}
+
+		@Override
+		public boolean isEnabled() {
+			return true;
+		}
+
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MapCustomUserRepository.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.util.Map;
+
+public class MapCustomUserRepository implements CustomUserRepository {
+
+	private final Map<String, CustomUser> emailToCustomUser;
+
+	public MapCustomUserRepository(Map<String, CustomUser> emailToCustomUser) {
+		this.emailToCustomUser = emailToCustomUser;
+	}
+
+	@Override
+	public CustomUser findCustomUserByEmail(String email) {
+		return this.emailToCustomUser.get(email);
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaApplication.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.security.crypto.codec.Hex;
+import org.springframework.security.crypto.encrypt.BytesEncryptor;
+
+/**
+ * Hello Security application.
+ *
+ * @author Josh Cummings
+ */
+@SpringBootApplication
+public class MfaApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(MfaApplication.class, args);
+	}
+
+	@Bean
+	MapCustomUserRepository userRepository(BytesEncryptor encryptor) {
+		// the hashed password was calculated using the following code
+		// the hash should be done up front, so malicious users cannot discover the
+		// password
+		// PasswordEncoder encoder =
+		// PasswordEncoderFactories.createDelegatingPasswordEncoder();
+		// String encodedPassword = encoder.encode("password");
+
+		// the raw password is "password"
+		String encodedPassword = "{bcrypt}$2a$10$h/AJueu7Xt9yh3qYuAXtk.WZJ544Uc2kdOKlHu2qQzCh/A3rq46qm";
+
+		// to sync your phone with the Google Authenticator secret, hand enter the value
+		// in base32Key
+		// String base32Key = "QDWSM3OYBPGTEVSPB5FKVDM3CSNCWHVK";
+		// Base32 base32 = new Base32();
+		// byte[] b = base32.decode(base32Key);
+		// String secret = Hex.encodeHexString(b);
+
+		String hexSecret = "80ed266dd80bcd32564f0f4aaa8d9b149a2b1eaa";
+		String encrypted = new String(Hex.encode(encryptor.encrypt(hexSecret.getBytes())));
+
+		// the raw security answer is "smith"
+		String encodedSecurityAnswer = "{bcrypt}$2a$10$JIXMjAszy3RUu8y5T0zH0enGJCGumI8YE.K7w3wsM5xXDfeVIsJhq";
+
+		CustomUser customUser = new CustomUser(1L, "user@example.com", encodedPassword, encrypted,
+				encodedSecurityAnswer);
+		Map<String, CustomUser> emailToCustomUser = new HashMap<>();
+		emailToCustomUser.put(customUser.getEmail(), customUser);
+		return new MapCustomUserRepository(emailToCustomUser);
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaAuthentication.java

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+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.util.Collections;
+
+import org.springframework.security.authentication.AbstractAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.CredentialsContainer;
+
+public class MfaAuthentication extends AbstractAuthenticationToken {
+
+	private final Authentication first;
+
+	public MfaAuthentication(Authentication first) {
+		super(Collections.emptyList());
+		this.first = first;
+	}
+
+	@Override
+	public Object getPrincipal() {
+		return this.first.getPrincipal();
+	}
+
+	@Override
+	public Object getCredentials() {
+		return this.first.getCredentials();
+	}
+
+	@Override
+	public void eraseCredentials() {
+		if (this.first instanceof CredentialsContainer) {
+			((CredentialsContainer) this.first).eraseCredentials();
+		}
+	}
+
+	@Override
+	public boolean isAuthenticated() {
+		return false;
+	}
+
+	public Authentication getFirst() {
+		return this.first;
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaAuthenticationHandler.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.io.IOException;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.security.authentication.AnonymousAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.core.authority.AuthorityUtils;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.web.authentication.AuthenticationFailureHandler;
+import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
+import org.springframework.security.web.authentication.SimpleUrlAuthenticationSuccessHandler;
+
+/**
+ * An authentication handler that saves an authentication either way.
+ *
+ * The reason for this is so that the rest of the factors are collected, even if earlier
+ * factors failed.
+ *
+ * @author Josh Cummings
+ */
+public class MfaAuthenticationHandler implements AuthenticationSuccessHandler, AuthenticationFailureHandler {
+
+	private final AuthenticationSuccessHandler successHandler;
+
+	public MfaAuthenticationHandler(String url) {
+		SimpleUrlAuthenticationSuccessHandler successHandler = new SimpleUrlAuthenticationSuccessHandler(url);
+		successHandler.setAlwaysUseDefaultTargetUrl(true);
+		this.successHandler = successHandler;
+	}
+
+	@Override
+	public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
+			AuthenticationException exception) throws IOException, ServletException {
+		Authentication anonymous = new AnonymousAuthenticationToken("key", "anonymousUser",
+				AuthorityUtils.createAuthorityList("ROLE_ANONYMOUS"));
+		saveMfaAuthentication(request, response, new MfaAuthentication(anonymous));
+	}
+
+	@Override
+	public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
+			Authentication authentication) throws IOException, ServletException {
+		saveMfaAuthentication(request, response, authentication);
+	}
+
+	private void saveMfaAuthentication(HttpServletRequest request, HttpServletResponse response,
+			Authentication authentication) throws IOException, ServletException {
+		SecurityContextHolder.getContext().setAuthentication(new MfaAuthentication(authentication));
+		this.successHandler.onAuthenticationSuccess(request, response, authentication);
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaController.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.security.SecureRandom;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.security.authentication.BadCredentialsException;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.crypto.codec.Hex;
+import org.springframework.security.crypto.encrypt.BytesEncryptor;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.web.authentication.AuthenticationFailureHandler;
+import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@Controller
+public class MfaController {
+
+	private final MfaService mfaService;
+
+	private final BytesEncryptor encryptor;
+
+	private final PasswordEncoder encoder;
+
+	private final AuthenticationSuccessHandler successHandler;
+
+	private final AuthenticationFailureHandler failureHandler;
+
+	private final String failedAuthenticationSecret;
+
+	private final String failedAuthenticationSecurityAnswer;
+
+	public MfaController(MfaService mfaService, BytesEncryptor encryptor, PasswordEncoder encoder,
+			AuthenticationSuccessHandler successHandler, AuthenticationFailureHandler failureHandler) {
+
+		this.mfaService = mfaService;
+		this.encryptor = encryptor;
+		this.encoder = encoder;
+		this.successHandler = successHandler;
+		this.failureHandler = failureHandler;
+
+		this.failedAuthenticationSecret = randomValue();
+		this.failedAuthenticationSecurityAnswer = this.encoder.encode(randomValue());
+	}
+
+	@GetMapping("/second-factor")
+	public String requestSecondFactor() {
+		return "second-factor";
+	}
+
+	@PostMapping("/second-factor")
+	public void processSecondFactor(@RequestParam("code") String code, MfaAuthentication authentication,
+			HttpServletRequest request, HttpServletResponse response) throws Exception {
+		MfaAuthenticationHandler handler = new MfaAuthenticationHandler("/third-factor");
+		String secret = getSecret(authentication);
+		if (this.mfaService.check(secret, code)) {
+			handler.onAuthenticationSuccess(request, response, authentication.getFirst());
+		}
+		else {
+			handler.onAuthenticationFailure(request, response, new BadCredentialsException("bad credentials"));
+		}
+	}
+
+	@GetMapping("/third-factor")
+	public String requestThirdFactor() {
+		return "third-factor";
+	}
+
+	@PostMapping("/third-factor")
+	public void processThirdFactor(@RequestParam("answer") String answer, MfaAuthentication authentication,
+			HttpServletRequest request, HttpServletResponse response) throws Exception {
+		String encodedAnswer = getAnswer(authentication);
+		if (this.encoder.matches(answer, encodedAnswer)) {
+			SecurityContextHolder.getContext().setAuthentication(authentication.getFirst());
+			this.successHandler.onAuthenticationSuccess(request, response, authentication.getFirst());
+		}
+		else {
+			this.failureHandler.onAuthenticationFailure(request, response,
+					new BadCredentialsException("bad credentials"));
+		}
+	}
+
+	private String getSecret(MfaAuthentication authentication) throws Exception {
+		if (authentication.getPrincipal() instanceof CustomUser) {
+			CustomUser user = (CustomUser) authentication.getPrincipal();
+			byte[] bytes = Hex.decode(user.getSecret());
+			return new String(this.encryptor.decrypt(bytes));
+		}
+		// earlier factor failed
+		return this.failedAuthenticationSecret;
+	}
+
+	private String getAnswer(MfaAuthentication authentication) {
+		if (authentication.getPrincipal() instanceof CustomUser) {
+			CustomUser user = (CustomUser) authentication.getPrincipal();
+			return user.getAnswer();
+		}
+		// earlier factor failed
+		return this.failedAuthenticationSecurityAnswer;
+	}
+
+	private static String randomValue() {
+		SecureRandom random = new SecureRandom();
+		byte[] bytes = new byte[20];
+		random.nextBytes(bytes);
+		return new String(Hex.encode(bytes));
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaService.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import java.security.GeneralSecurityException;
+
+import com.j256.twofactorauth.TimeBasedOneTimePasswordUtil;
+
+import org.springframework.stereotype.Service;
+
+@Service
+public class MfaService {
+
+	public boolean check(String hexKey, String code) {
+		try {
+			return TimeBasedOneTimePasswordUtil.validateCurrentNumberHex(hexKey, Integer.parseInt(code), 10000);
+		}
+		catch (GeneralSecurityException ex) {
+			throw new IllegalArgumentException(ex);
+		}
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/MfaTrustResolver.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import org.springframework.security.authentication.AuthenticationTrustResolver;
+import org.springframework.security.authentication.AuthenticationTrustResolverImpl;
+import org.springframework.security.core.Authentication;
+
+public class MfaTrustResolver implements AuthenticationTrustResolver {
+
+	private final AuthenticationTrustResolver delegate = new AuthenticationTrustResolverImpl();
+
+	@Override
+	public boolean isAnonymous(Authentication authentication) {
+		return this.delegate.isAnonymous(authentication) || authentication instanceof MfaAuthentication;
+	}
+
+	@Override
+	public boolean isRememberMe(Authentication authentication) {
+		return this.delegate.isRememberMe(authentication);
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/java/example/SecurityConfig.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package example;
+
+import javax.crypto.KeyGenerator;
+import javax.crypto.SecretKey;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.authorization.AuthorizationDecision;
+import org.springframework.security.authorization.AuthorizationManager;
+import org.springframework.security.config.annotation.ObjectPostProcessor;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.crypto.encrypt.AesBytesEncryptor;
+import org.springframework.security.crypto.factory.PasswordEncoderFactories;
+import org.springframework.security.crypto.keygen.KeyGenerators;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.access.ExceptionTranslationFilter;
+import org.springframework.security.web.access.intercept.RequestAuthorizationContext;
+import org.springframework.security.web.authentication.AuthenticationFailureHandler;
+import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
+import org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler;
+import org.springframework.security.web.authentication.SimpleUrlAuthenticationFailureHandler;
+
+@Configuration
+public class SecurityConfig {
+
+	@Bean
+	SecurityFilterChain web(HttpSecurity http,
+			AuthorizationManager<RequestAuthorizationContext> mfaAuthorizationManager) throws Exception {
+		MfaAuthenticationHandler mfaAuthenticationHandler = new MfaAuthenticationHandler("/second-factor");
+		http.authorizeHttpRequests((authz) -> authz.mvcMatchers("/second-factor", "/third-factor")
+				.access(mfaAuthorizationManager).anyRequest().authenticated())
+				.formLogin((form) -> form.successHandler(mfaAuthenticationHandler)
+						.failureHandler(mfaAuthenticationHandler))
+				.exceptionHandling((exceptions) -> exceptions
+						.withObjectPostProcessor(new ObjectPostProcessor<ExceptionTranslationFilter>() {
+							@Override
+							public <O extends ExceptionTranslationFilter> O postProcess(O filter) {
+								filter.setAuthenticationTrustResolver(new MfaTrustResolver());
+								return filter;
+							}
+						}));
+
+		return http.build();
+	}
+
+	@Bean
+	AuthorizationManager<RequestAuthorizationContext> mfaAuthorizationManager() {
+		return (authentication,
+				context) -> new AuthorizationDecision(authentication.get() instanceof MfaAuthentication);
+	}
+
+	// for the second-factor
+	@Bean
+	AesBytesEncryptor encryptor() throws Exception {
+		KeyGenerator generator = KeyGenerator.getInstance("AES");
+		generator.init(128);
+		SecretKey key = generator.generateKey();
+		return new AesBytesEncryptor(key, KeyGenerators.secureRandom(12), AesBytesEncryptor.CipherAlgorithm.GCM);
+	}
+
+	// for the third-factor
+	@Bean
+	PasswordEncoder encoder() {
+		return PasswordEncoderFactories.createDelegatingPasswordEncoder();
+	}
+
+	@Bean
+	AuthenticationSuccessHandler successHandler() {
+		return new SavedRequestAwareAuthenticationSuccessHandler();
+	}
+
+	@Bean
+	AuthenticationFailureHandler failureHandler() {
+		return new SimpleUrlAuthenticationFailureHandler("/login?error");
+	}
+
+}

servlet/spring-boot/java/authentication/username-password/mfa/src/main/resources/templates/index.html

@@ -0,0 +1,9 @@
+<html xmlns:th="https://www.thymeleaf.org">
+<head>
+    <title>Hello Security!</title>
+</head>
+<body>
+    <h1>Hello Security</h1>
+    <a th:href="@{/logout}">Log Out</a>
+</body>
+</html>

servlet/spring-boot/java/authentication/username-password/mfa/src/main/resources/templates/second-factor.html

@@ -0,0 +1,24 @@
+<!--
+  ~ Copyright 2021 the original author or authors.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      https://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="https://www.thymeleaf.org">
+    <body>
+        <form th:action="@{/second-factor}" method="post">
+            <input name="code" placeholder="Enter Code"/>
+            <input type="submit" value="Submit"/>
+        </form>
+    </body>
+</html>

servlet/spring-boot/java/authentication/username-password/mfa/src/main/resources/templates/third-factor.html

@@ -0,0 +1,24 @@
+<!--
+  ~ Copyright 2021 the original author or authors.
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      https://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="https://www.thymeleaf.org">
+    <body>
+        <form th:action="@{/third-factor}" method="post">
+            <input name="answer" placeholder="Mother's Maiden Name"/>
+            <input type="submit" value="Submit"/>
+        </form>
+    </body>
+</html>

servlet/spring-boot/java/authentication/username-password/mfa/src/test/java/example/MfaApplicationTests.java

@@ -0,0 +1,188 @@
+/*
+ * Copyright 2021 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import javax.servlet.http.HttpSession;
+
+import com.j256.twofactorauth.TimeBasedOneTimePasswordUtil;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.mock.web.MockHttpSession;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.MvcResult;
+
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestBuilders.formLogin;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.csrf;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.redirectedUrl;
+
+/**
+ * @author Rob Winch
+ */
+@SpringBootTest
+@AutoConfigureMockMvc
+public class MfaApplicationTests {
+
+	private static final String hexKey = "80ed266dd80bcd32564f0f4aaa8d9b149a2b1eaa";
+
+	@Autowired
+	private MockMvc mockMvc;
+
+	@Test
+	void mfaWhenAllFactorsSucceedMatchesThenWorks() throws Exception {
+		// @formatter:off
+		MvcResult result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("password"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		HttpSession session = result.getRequest().getSession();
+
+		Integer code = TimeBasedOneTimePasswordUtil.generateCurrentNumberHex(hexKey);
+		this.mockMvc.perform(post("/second-factor")
+				.session((MockHttpSession) session)
+				.param("code", String.valueOf(code))
+				.with(csrf()))
+				.andExpect(redirectedUrl("/third-factor"));
+
+		this.mockMvc.perform(post("/third-factor")
+				.session((MockHttpSession) session)
+				.param("answer", "smith")
+				.with(csrf()))
+				.andExpect(redirectedUrl("/"));
+		// @formatter:on
+	}
+
+	@Test
+	void mfaWhenBadCredsThenStillRequestsRemainingFactorsAndRedirects() throws Exception {
+		// @formatter:off
+		MvcResult result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("wrongpassword"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		HttpSession session = result.getRequest().getSession();
+
+		Integer code = TimeBasedOneTimePasswordUtil.generateCurrentNumberHex(hexKey);
+		this.mockMvc.perform(post("/second-factor")
+				.session((MockHttpSession) session)
+				.param("code", String.valueOf(code))
+				.with(csrf()))
+				.andExpect(redirectedUrl("/third-factor"));
+
+		this.mockMvc.perform(post("/third-factor")
+				.session((MockHttpSession) session)
+				.param("answer", "smith")
+				.with(csrf()))
+				.andExpect(redirectedUrl("/login?error"));
+		// @formatter:on
+	}
+
+	@Test
+	void mfaWhenWrongCodeThenRedirects() throws Exception {
+		// @formatter:off
+		MvcResult result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("password"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		HttpSession session = result.getRequest().getSession();
+
+		Integer code = TimeBasedOneTimePasswordUtil.generateCurrentNumberHex(hexKey) - 1;
+		this.mockMvc.perform(post("/second-factor")
+				.session((MockHttpSession) session)
+				.param("code", String.valueOf(code))
+				.with(csrf()))
+				.andExpect(redirectedUrl("/third-factor"));
+
+		this.mockMvc.perform(post("/third-factor")
+				.session((MockHttpSession) session)
+				.param("answer", "smith")
+				.with(csrf()))
+				.andExpect(redirectedUrl("/login?error"));
+		// @formatter:on
+	}
+
+	@Test
+	void mfaWhenWrongSecurityAnswerThenRedirects() throws Exception {
+		// @formatter:off
+		MvcResult result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("password"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		HttpSession session = result.getRequest().getSession();
+
+		Integer code = TimeBasedOneTimePasswordUtil.generateCurrentNumberHex(hexKey);
+		this.mockMvc.perform(post("/second-factor")
+				.session((MockHttpSession) session)
+				.param("code", String.valueOf(code))
+				.with(csrf()))
+				.andExpect(redirectedUrl("/third-factor"));
+
+		this.mockMvc.perform(post("/third-factor")
+				.session((MockHttpSession) session)
+				.param("answer", "wilson")
+				.with(csrf()))
+				.andExpect(redirectedUrl("/login?error"));
+		// @formatter:on
+	}
+
+	@Test
+	void mfaWhenInProcessThenCantViewOtherPages() throws Exception {
+		// @formatter:off
+		MvcResult result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("password"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		HttpSession session = result.getRequest().getSession();
+
+		this.mockMvc.perform(get("/")
+				.session((MockHttpSession) session))
+				.andExpect(redirectedUrl("http://localhost/login"));
+
+		result = this.mockMvc.perform(formLogin()
+				.user("user@example.com")
+				.password("password"))
+				.andExpect(redirectedUrl("/second-factor"))
+				.andReturn();
+
+		session = result.getRequest().getSession();
+
+		Integer code = TimeBasedOneTimePasswordUtil.generateCurrentNumberHex(hexKey);
+		this.mockMvc.perform(post("/second-factor")
+				.session((MockHttpSession) session)
+				.param("code", String.valueOf(code))
+				.with(csrf()))
+				.andExpect(redirectedUrl("/third-factor"));
+
+		this.mockMvc.perform(get("/")
+				.session((MockHttpSession) session))
+				.andExpect(redirectedUrl("http://localhost/login"));
+		// @formatter:on
+	}
+
+}