With most of your samples we’re using DummyUserDetailsService because there is not necessarily need to query a real user details once kerberos authentication is successful and we can use kerberos principal info to create that dummy user. However there is a way to access kerberized LDAP services in a say way and query user details from there.

KerberosLdapContextSource can be used to bind into LDAP via kerberos which is at least proven to work well with Windows AD services.

@Value("${app.ad-server}")
private String adServer;

@Value("${app.service-principal}")
private String servicePrincipal;

@Value("${app.keytab-location}")
private String keytabLocation;

@Value("${app.ldap-search-base}")
private String ldapSearchBase;

@Value("${app.ldap-search-filter}")
private String ldapSearchFilter;

@Bean
public KerberosLdapContextSource kerberosLdapContextSource() {
    KerberosLdapContextSource contextSource = new KerberosLdapContextSource(adServer);
    SunJaasKrb5LoginConfig loginConfig = new SunJaasKrb5LoginConfig();
    loginConfig.setKeyTabLocation(new FileSystemResource(keytabLocation));
    loginConfig.setServicePrincipal(servicePrincipal);
    loginConfig.setDebug(true);
    loginConfig.setIsInitiator(true);
    contextSource.setLoginConfig(loginConfig);
    return contextSource;
}

@Bean
public LdapUserDetailsService ldapUserDetailsService() {
    FilterBasedLdapUserSearch userSearch =
            new FilterBasedLdapUserSearch(ldapSearchBase, ldapSearchFilter, kerberosLdapContextSource());
    LdapUserDetailsService service = new LdapUserDetailsService(userSearch);
    service.setUserDetailsMapper(new LdapUserDetailsMapper());
    return service;
}