diff --git a/impl/extension/servlet/src/main/java/br/gov/frameworkdemoiselle/security/ServletAuthenticator.java b/impl/extension/servlet/src/main/java/br/gov/frameworkdemoiselle/security/ServletAuthenticator.java
index e48cc29..cd37da0 100644
--- a/impl/extension/servlet/src/main/java/br/gov/frameworkdemoiselle/security/ServletAuthenticator.java
+++ b/impl/extension/servlet/src/main/java/br/gov/frameworkdemoiselle/security/ServletAuthenticator.java
@@ -65,11 +65,14 @@ public class ServletAuthenticator implements Authenticator {
 	@Override
 	public void authenticate() throws AuthenticationException {
 		try {
-			if (getRequest().getUserPrincipal() == null) {
-				getRequest().login(getCredentials().getUsername(), getCredentials().getPassword());
-			}
+			getRequest().login(getCredentials().getUsername(), getCredentials().getPassword());
+
 		} catch (ServletException cause) {
-			throw new AuthenticationException(getBundle().getString("authentication-failed"), cause);
+			if (cause.getMessage().contains("invalid")) {
+				throw new InvalidCredentialsException(getBundle().getString("invalid-credentials"));
+			} else {
+				throw new AuthenticationException(getBundle().getString("authentication-failed"), cause);
+			}
 		}
 	}
 
diff --git a/impl/extension/servlet/src/main/resources/demoiselle-servlet-bundle.properties b/impl/extension/servlet/src/main/resources/demoiselle-servlet-bundle.properties
index fb4f36f..59e36d6 100644
--- a/impl/extension/servlet/src/main/resources/demoiselle-servlet-bundle.properties
+++ b/impl/extension/servlet/src/main/resources/demoiselle-servlet-bundle.properties
@@ -34,4 +34,5 @@
 # 51 Franklin St, Fifth Floor, Boston, MA 02111-1301, USA.
 
 has-permission-not-supported=N\u00E3o \u00E9 poss\u00EDvel utilizar @{0}, pois esta funcionalidade n\u00E3o \u00E9 suportada pelo JAAS.
+invalid-credentials=Usu\u00E1rio ou senha inv\u00E1lidos.
 authentication-failed=Falha no processo de autentica\u00E7\u00E3o.
diff --git a/impl/extension/servlet/src/test/java/security/authentication/form/HelperServlet.java b/impl/extension/servlet/src/test/java/security/authentication/form/HelperServlet.java
index 78cf981..fc5a5d6 100644
--- a/impl/extension/servlet/src/test/java/security/authentication/form/HelperServlet.java
+++ b/impl/extension/servlet/src/test/java/security/authentication/form/HelperServlet.java
@@ -2,13 +2,9 @@ package security.authentication.form;
 
 import static org.apache.http.HttpStatus.SC_EXPECTATION_FAILED;
 import static org.apache.http.HttpStatus.SC_FORBIDDEN;
-import static org.apache.http.HttpStatus.SC_NOT_FOUND;
 import static org.apache.http.HttpStatus.SC_OK;
 
 import java.io.IOException;
-import java.security.InvalidParameterException;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
@@ -26,14 +22,10 @@ public class HelperServlet extends HttpServlet {
 
 	@Override
 	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
-		String action = getAction(request);
-
-		if ("login".equals(action)) {
+		if (request.getRequestURI().endsWith("/login")) {
 			login(request, response);
-		} else if ("logout".equals(action)) {
-			logout(request, response);
 		} else {
-			response.setStatus(SC_NOT_FOUND);
+			logout(request, response);
 		}
 	}
 
@@ -74,15 +66,4 @@ public class HelperServlet extends HttpServlet {
 		credentials.setUsername(request.getParameter("username"));
 		credentials.setPassword(request.getParameter("password"));
 	}
-
-	private String getAction(HttpServletRequest request) {
-		Pattern pattern = Pattern.compile("^.+/(.+)$");
-		Matcher matcher = pattern.matcher(request.getRequestURI());
-
-		if (matcher.matches()) {
-			return matcher.group(1).toLowerCase();
-		} else {
-			throw new InvalidParameterException("Está faltando o parâmetro de ação na URL");
-		}
-	}
 }
diff --git a/impl/extension/servlet/src/test/resources/security/authentication/form/web.xml b/impl/extension/servlet/src/test/resources/security/authentication/form/web.xml
index ac8afc4..a3a356a 100644
--- a/impl/extension/servlet/src/test/resources/security/authentication/form/web.xml
+++ b/impl/extension/servlet/src/test/resources/security/authentication/form/web.xml
@@ -56,6 +56,7 @@
 	</servlet>
 	<servlet-mapping>
 		<servlet-name>Helper Servlet</servlet-name>
-		<url-pattern>/helper/*</url-pattern>
+		<url-pattern>/helper/login</url-pattern>
+		<url-pattern>/helper/logout</url-pattern>
 	</servlet-mapping>
 </web-app>
\ No newline at end of file
--
libgit2 0.21.2