diff --git a/core/src/main/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilter.java b/core/src/main/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilter.java
index f6b8fe113d..77e2a3a5ca 100644
--- a/core/src/main/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilter.java
+++ b/core/src/main/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilter.java
@@ -17,6 +17,7 @@ package org.springframework.security.ui.webapp;
 
 import org.springframework.security.Authentication;
 import org.springframework.security.AuthenticationException;
+import org.springframework.security.AuthenticationServiceException;
 
 import org.springframework.security.providers.UsernamePasswordAuthenticationToken;
 
@@ -54,6 +55,7 @@ public class AuthenticationProcessingFilter extends AbstractProcessingFilter {
 
     private String usernameParameter = SPRING_SECURITY_FORM_USERNAME_KEY;
     private String passwordParameter = SPRING_SECURITY_FORM_PASSWORD_KEY;
+    private boolean postOnly = true;
 
     //~ Constructors ===================================================================================================
 
@@ -64,6 +66,10 @@ public class AuthenticationProcessingFilter extends AbstractProcessingFilter {
     //~ Methods ========================================================================================================
 
     public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException {
+        if (postOnly && !request.getMethod().equals("POST")) {
+            throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());
+        }
+
         String username = obtainUsername(request);
         String password = obtainPassword(request);
 
@@ -151,6 +157,18 @@ public class AuthenticationProcessingFilter extends AbstractProcessingFilter {
         this.passwordParameter = passwordParameter;
     }
 
+    /**
+     * Defines whether only HTTP POST requests will be allowed by this filter.
+     * If set to true, and an authentication request is received which is not a POST request, an exception will
+     * be raised immediately and authentication will not be attempted. The <tt>unsuccessfulAuthentication()</tt> method
+     * will be called as if handling a failed authentication.
+     * <p>
+     * Defaults to <tt>true</tt> but may be overridden by subclasses.
+     */
+    public void setPostOnly(boolean postOnly) {
+        this.postOnly = postOnly;
+    }
+
     public int getOrder() {
         return FilterChainOrder.AUTHENTICATION_PROCESSING_FILTER;
     }
diff --git a/core/src/test/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilterTests.java b/core/src/test/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilterTests.java
index 2daef04992..9d3393bd63 100644
--- a/core/src/test/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilterTests.java
+++ b/core/src/test/java/org/springframework/security/ui/webapp/AuthenticationProcessingFilterTests.java
@@ -19,6 +19,7 @@ import javax.servlet.ServletException;
 
 import junit.framework.TestCase;
 
+import org.junit.Test;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.security.Authentication;
@@ -36,17 +37,14 @@ import org.springframework.security.ui.WebAuthenticationDetails;
 public class AuthenticationProcessingFilterTests extends TestCase {
     //~ Methods ========================================================================================================
 
-    public void testGetters() {
-        AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
-        assertEquals("/j_spring_security_check", filter.getFilterProcessesUrl());
-    }
-
+    @Test
     public void testNormalOperation() throws Exception {
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_USERNAME_KEY, "rod");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_PASSWORD_KEY, "koala");
 
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
+        assertEquals("/j_spring_security_check", filter.getFilterProcessesUrl());
         filter.setAuthenticationManager(new MockAuthenticationManager(true));
         filter.init(null);
 
@@ -57,8 +55,9 @@ public class AuthenticationProcessingFilterTests extends TestCase {
         assertEquals("127.0.0.1", ((WebAuthenticationDetails) result.getDetails()).getRemoteAddress());
     }
 
+    @Test
     public void testNullPasswordHandledGracefully() throws Exception {
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_USERNAME_KEY, "rod");
 
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
@@ -68,8 +67,9 @@ public class AuthenticationProcessingFilterTests extends TestCase {
         assertTrue(result != null);
     }
 
+    @Test
     public void testNullUsernameHandledGracefully() throws Exception {
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_PASSWORD_KEY, "koala");
 
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
@@ -79,13 +79,14 @@ public class AuthenticationProcessingFilterTests extends TestCase {
         assertTrue(result != null);
     }
 
+    @Test
     public void testUsingDifferentParameterNamesWorksAsExpected() throws ServletException {
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
         filter.setAuthenticationManager(new MockAuthenticationManager(true));
         filter.setUsernameParameter("x");
         filter.setPasswordParameter("y");
 
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter("x", "rod");
         request.addParameter("y", "koala");
 
@@ -94,8 +95,9 @@ public class AuthenticationProcessingFilterTests extends TestCase {
         assertEquals("127.0.0.1", ((WebAuthenticationDetails) result.getDetails()).getRemoteAddress());
     }
 
+    @Test
     public void testSpacesAreTrimmedCorrectlyFromUsername() throws Exception {
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_USERNAME_KEY, " rod ");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_PASSWORD_KEY, "koala");
 
@@ -106,8 +108,9 @@ public class AuthenticationProcessingFilterTests extends TestCase {
         assertEquals("rod", result.getName());
     }
 
+    @Test
     public void testFailedAuthenticationThrowsException() {
-        MockHttpServletRequest request = new MockHttpServletRequest();
+        MockHttpServletRequest request = new MockHttpServletRequest("POST", "/");
         request.addParameter(AuthenticationProcessingFilter.SPRING_SECURITY_FORM_USERNAME_KEY, "rod");
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();
         filter.setAuthenticationManager(new MockAuthenticationManager(false));
@@ -126,7 +129,8 @@ public class AuthenticationProcessingFilterTests extends TestCase {
     /**
      * SEC-571
      */
-    public void testNoSessionIsCreatedIfAllowSessionCreationIsFalse() throws Exception {
+    @Test
+    public void noSessionIsCreatedIfAllowSessionCreationIsFalse() throws Exception {
         MockHttpServletRequest request = new MockHttpServletRequest();
 
         AuthenticationProcessingFilter filter = new AuthenticationProcessingFilter();