Source:
public void authenticateInbound(MuleEvent event) throws SecurityException, SecurityProviderNotFoundException, UnknownAuthenticationTypeException { String header = event.getMessage().getInboundProperty(HttpConstants.HEADER_AUTHORIZATION); if (logger.isDebugEnabled()) { logger.debug("Authorization header: " + header); } if ((header != null) && header.startsWith("Basic ")) { String base64Token = header.substring(6); String token = new String(Base64.decodeBase64(base64Token.getBytes())); String username = ""; String password = ""; int delim = token.indexOf(":"); if (delim != -1) { username = token.substring(0, delim); password = token.substring(delim + 1); } Authentication authResult; Authentication authentication = createAuthentication(username, password, event); try { authResult = getSecurityManager().authenticate(authentication); } catch (UnauthorisedException e) { if (logger.isDebugEnabled()) { logger.debug("Authentication request for user: " + username + " failed: " + e.toString()); logger.debug("Cause: " + e.getCause().getMessage()); } setUnauthenticated(event); throw new UnauthorisedException(CoreMessages.authFailedForUser(username), event, e); } if (logger.isDebugEnabled()) { logger.debug("Authentication success: " + authResult.toString()); } SecurityContext context = getSecurityManager().createSecurityContext(authResult); context.setAuthentication(authResult); event.getSession().setSecurityContext(context); } else if (header == null) { setUnauthenticated(event); throw new UnauthorisedException(event, event.getSession().getSecurityContext(), this); } else { setUnauthenticated(event); throw new UnsupportedAuthenticationSchemeException( HttpMessages.basicFilterCannotHandleHeader(header), event); } }

Target:
public void authenticateInbound(MuleEvent event) throws SecurityException, SecurityProviderNotFoundException, UnknownAuthenticationTypeException { String header = event.getMessage().getInboundProperty(HttpConstants.HEADER_AUTHORIZATION); if (logger.isDebugEnabled()) { logger.debug("Authorization header: " + header); } if ((header != null) && header.startsWith("Basic ")) { String base64Token = header.substring(6); String token = new String(Base64.decodeBase64(base64Token.getBytes())); String username = ""; String password = ""; int delim = token.indexOf(":"); if (delim != -1) { username = token.substring(0, delim); password = token.substring(delim + 1); } Authentication authResult; Authentication authentication = createAuthentication(username, password, event); try { authResult = getSecurityManager().authenticate(authentication); } catch (UnauthorisedException e) { if (logger.isDebugEnabled()) { logger.debug(format("Authentication request for user: '%s' failed: '%s'\nCause: '%s'", username, e.toString(), e.getCause().getMessage())); } setUnauthenticated(event); throw new UnauthorisedException(CoreMessages.authFailedForUser(username), event, e); } if (logger.isDebugEnabled()) { logger.debug("Authentication success: " + authResult.toString()); } SecurityContext context = getSecurityManager().createSecurityContext(authResult); context.setAuthentication(authResult); event.getSession().setSecurityContext(context); } else if (header == null) { setUnauthenticated(event); throw new UnauthorisedException(event, event.getSession().getSecurityContext(), this); } else { setUnauthenticated(event); throw new UnsupportedAuthenticationSchemeException( HttpMessages.basicFilterCannotHandleHeader(header), event); } }