I got it working. try this configuration in you login-config.xml
<application-policy name="myTestWAR">
<authentication>
<login-module code="org.jboss.security.auth.spi.LdapLoginModule" flag="required" >
<module-option name="java.naming.factory.initial">com.sun.jndi.ldap.LdapCtxFactory</module-option>
<module-option name="java.naming.provider.url">
ldap://localhost:389</module-option>
<module-option name="java.naming.security.authentication">simple</module-option>
<module-option name="bindDN">uid=admin,ou=system</module-option>
<module-option name="bindCredential">secret</module-option>
<module-option name="principalDNPrefix">uid=</module-option>
<module-option name="principalDNSuffix">,ou=system</module-option>
<module-option name="searchScope">ONELEVEL_SCOPE</module-option>
<module-option name="allowEmptyPasswords">true</module-option>
</login-module>
</authentication>
</application-policy>