diff --git a/web/src/main/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilter.java b/web/src/main/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilter.java
index 3c1103270f0..b83663fc82c 100644
--- a/web/src/main/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilter.java
+++ b/web/src/main/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -18,9 +18,18 @@
 
 import reactor.core.publisher.Mono;
 
+import org.springframework.context.MessageSource;
+import org.springframework.context.MessageSourceAware;
+import org.springframework.context.support.MessageSourceAccessor;
 import org.springframework.http.HttpStatus;
 import org.springframework.security.access.AccessDeniedException;
 import org.springframework.security.authentication.AuthenticationCredentialsNotFoundException;
+import org.springframework.security.authentication.AuthenticationTrustResolver;
+import org.springframework.security.authentication.AuthenticationTrustResolverImpl;
+import org.springframework.security.authentication.InsufficientAuthenticationException;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.core.SpringSecurityMessageSource;
 import org.springframework.security.web.server.ServerAuthenticationEntryPoint;
 import org.springframework.security.web.server.authentication.HttpBasicServerAuthenticationEntryPoint;
 import org.springframework.util.Assert;
@@ -30,20 +39,30 @@
 
 /**
  * @author Rob Winch
+ * @author César Revert
  * @since 5.0
  */
-public class ExceptionTranslationWebFilter implements WebFilter {
+public class ExceptionTranslationWebFilter implements WebFilter, MessageSourceAware {
 
 	private ServerAuthenticationEntryPoint authenticationEntryPoint = new HttpBasicServerAuthenticationEntryPoint();
 
 	private ServerAccessDeniedHandler accessDeniedHandler = new HttpStatusServerAccessDeniedHandler(
 			HttpStatus.FORBIDDEN);
 
+	private AuthenticationTrustResolver authenticationTrustResolver = new AuthenticationTrustResolverImpl();
+
+	protected MessageSourceAccessor messages = SpringSecurityMessageSource.getAccessor();
+
 	@Override
 	public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
-		return chain.filter(exchange).onErrorResume(AccessDeniedException.class,
-				(denied) -> exchange.getPrincipal().switchIfEmpty(commenceAuthentication(exchange, denied))
-						.flatMap((principal) -> this.accessDeniedHandler.handle(exchange, denied)));
+		return chain.filter(exchange).onErrorResume(AccessDeniedException.class, (denied) -> exchange.getPrincipal()
+				.filter((principal) -> (!(principal instanceof Authentication) || (principal instanceof Authentication
+						&& !(this.authenticationTrustResolver.isAnonymous((Authentication) principal)))))
+				.switchIfEmpty(commenceAuthentication(exchange,
+						new InsufficientAuthenticationException(
+								this.messages.getMessage("ExceptionTranslationWebFilter.insufficientAuthentication",
+										"Full authentication is required to access this resource"))))
+				.flatMap((principal) -> this.accessDeniedHandler.handle(exchange, denied)).then());
 	}
 
 	/**
@@ -66,7 +85,28 @@ public void setAuthenticationEntryPoint(ServerAuthenticationEntryPoint authentic
 		this.authenticationEntryPoint = authenticationEntryPoint;
 	}
 
-	private <T> Mono<T> commenceAuthentication(ServerWebExchange exchange, AccessDeniedException denied) {
+	/**
+	 * Sets the authentication trust resolver.
+	 * @param authenticationTrustResolver the authentication trust resolver to use.
+	 * Default is {@link AuthenticationTrustResolverImpl}
+	 *
+	 * @since 5.5
+	 */
+	public void setAuthenticationTrustResolver(AuthenticationTrustResolver authenticationTrustResolver) {
+		Assert.notNull(authenticationTrustResolver, "authenticationTrustResolver must not be null");
+		this.authenticationTrustResolver = authenticationTrustResolver;
+	}
+
+	/**
+	 * @since 5.5
+	 */
+	@Override
+	public void setMessageSource(MessageSource messageSource) {
+		Assert.notNull(messageSource, "messageSource cannot be null");
+		this.messages = new MessageSourceAccessor(messageSource);
+	}
+
+	private <T> Mono<T> commenceAuthentication(ServerWebExchange exchange, AuthenticationException denied) {
 		return this.authenticationEntryPoint
 				.commence(exchange, new AuthenticationCredentialsNotFoundException("Not Authenticated", denied))
 				.then(Mono.empty());
diff --git a/web/src/test/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilterTests.java b/web/src/test/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilterTests.java
index 847edc204a8..b9ab463880d 100644
--- a/web/src/test/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilterTests.java
+++ b/web/src/test/java/org/springframework/security/web/server/authorization/ExceptionTranslationWebFilterTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -30,6 +30,7 @@
 import org.springframework.http.HttpStatus;
 import org.springframework.mock.http.server.reactive.MockServerHttpResponse;
 import org.springframework.security.access.AccessDeniedException;
+import org.springframework.security.authentication.AnonymousAuthenticationToken;
 import org.springframework.security.web.server.ServerAuthenticationEntryPoint;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilterChain;
@@ -41,6 +42,7 @@
 
 /**
  * @author Rob Winch
+ * @author César Revert
  * @since 5.0
  */
 @RunWith(MockitoJUnitRunner.class)
@@ -49,6 +51,9 @@ public class ExceptionTranslationWebFilterTests {
 	@Mock
 	private Principal principal;
 
+	@Mock
+	private AnonymousAuthenticationToken anonymousPrincipal;
+
 	@Mock
 	private ServerWebExchange exchange;
 
@@ -129,6 +134,15 @@ public void filterWhenAccessDeniedExceptionAndAuthenticatedThenHandled() {
 		this.entryPointPublisher.assertWasNotSubscribed();
 	}
 
+	@Test
+	public void filterWhenAccessDeniedExceptionAndAnonymousAuthenticatedThenHandled() {
+		given(this.exchange.getPrincipal()).willReturn(Mono.just(this.anonymousPrincipal));
+		given(this.chain.filter(this.exchange)).willReturn(Mono.error(new AccessDeniedException("Not Authorized")));
+		StepVerifier.create(this.filter.filter(this.exchange, this.chain)).expectComplete().verify();
+		this.deniedPublisher.assertWasNotSubscribed();
+		this.entryPointPublisher.assertWasSubscribed();
+	}
+
 	@Test
 	public void setAccessDeniedHandlerWhenNullThenException() {
 		assertThatIllegalArgumentException().isThrownBy(() -> this.filter.setAccessDeniedHandler(null));
@@ -139,4 +153,14 @@ public void setAuthenticationEntryPointWhenNullThenException() {
 		assertThatIllegalArgumentException().isThrownBy(() -> this.filter.setAuthenticationEntryPoint(null));
 	}
 
+	@Test
+	public void setAuthenticationTrustResolver() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.filter.setAuthenticationTrustResolver(null));
+	}
+
+	@Test
+	public void setMessageSource() {
+		assertThatIllegalArgumentException().isThrownBy(() -> this.filter.setMessageSource(null));
+	}
+
 }