Security recommendation

Secure configuration access

Configuration can be stored in several formats (SQL, File, LDAP) but must be shared over the network if you use more than 1 server. If some of your servers are not in the same (secured) network than the database, it is recommended to use SOAP access for those servers.


You can use different type of access: SQL, File or LDAP for servers in secured network and SOAP for remote servers.

Next, you have to configure the SOAP access as described here since SOAP access is denied by default.

Protect the Manager

By default, the manager is restricted to the user ‘dwho’ (default backend is Demo). To protect the manager, you have to choose one or both of :

  • protect the manager by Apache configuration

  • protect the manager by LL::NG

Protect the Manager by the web server

You can use any of the mechanisms proposed by Apache: SSL, Auth-Basic, Kerberos,… Example

<VirtualHost *:443>
    # SSL parameters
    # DocumentRoot
    DocumentRoot /var/lib/lemonldap-ng/manager/
    <Location />
        AuthType Basic
        AuthName "Lemonldap::NG manager"
        AuthUserFile /usr/local/apache/passwd/passwords
        Require user rbowen
        Order allow,deny
        Deny from all
        Allow from
        Options +ExecCGI

Protect the Manager by LL::NG

To protect the manager by LL::NG, you just have to set this in lemonldap-ng.ini configuration file (section [manager]):

protection = manager


Before, you have to create the virtual host manager.your.domain in the manager and set a rule, else access to the manager will be denied.


LLNG portal now embeds the following features:

  • CSRF protection (Cross-Site Request Forgery): a token is built for each form. To disable it, set ‘​require Token for forms’ ​to Off (portal security parameters in the manager). Token timeout can be defined via manager (default to 120 seconds)

  • Brute-force attack protection: after some failed logins, user must wait before re-try to log into Portal

  • Content-Security-Policy header: portal builds dynamically this header. You can modify default values in the manager (General parameters » Advanced parameters » Security » Content-Security-Policy)

  • Cross-Origin Resource Sharing headers: CORS is a mechanism that allows restricted resources on a web page to be requested from another domain outside the domain from which the first resource was served. A web page may freely embed cross-origin images, stylesheets, scripts, iframes, and videos. Certain “cross-domain” requests, notably Ajax requests, are forbidden by default by the same-origin security policy. You can modify default values in the manager (General parameters » Advanced parameters » Security » Cross-Origin Resource Sharing)

  • IP filtering: LemonLDAP::NG can use a CrowdSec server to filter connexion using IP reputation from CrowdSec. See CrowdSec Bouncer


  • Brute-force attack protection is DISABLED by default

  • Browser implementations of formAction directive are inconsistent (e.g. Firefox doesn’t block the redirects whereas Chrome does). Administrators may have to modify formAction value with wildcard likes *.

Split portal when using SOAP/REST

If you use SOAP or REST session backend, dedicate a portal especially for these internal requests.

Write good rules

Order your rules

Rules are applied in alphabetical order (comment and regular expression). The first matching rule is applied.


The “default” rule is only applied if no other rule matchs

The Manager let you define comments in rules, to order them:


For example, if these rules are used without comments:

Regular expression




$uid eq “root”



Then the second rule will be applied first, so every authenticated user will access to /pub/admin directory.

Use comment to correct this:

Regular expression




$uid eq “root”






  • Reload the Manager to see the effective order

  • Use rule comments to order your rules

Be careful with URL parameters

You can write rules matching any component of URL to protect including GET parameters, but be careful.

For example with this rule on the access parameter:

Regular expression




$groups =~ /\badmin\b/



Then a user that try to access to one of the following will be granted !

  • /index.php?access=admin&access=other

  • /index.php?Access=admin

You can use the following rules instead:

Regular expression







$groups =~ /\badmin\b/





(?i) means case no sensitive.


Remember that rules written on GET parameters must be tested.

Encoded characters

Some characters are encoded in URLs by the browser (such as space,…). To avoid problems, LL::NG decode them using So write your rules using normal characters.

IP in rules


If you are running LemonLDAP::NG behind a reverse proxy, make sure you check the Reverse Proxy how-to so that the rule applies to the real user IP and not the reverse proxy’s IP. Make sure you only specify trusted proxy addresses so that an attacker cannot forge the X-Forwarded-For header

Secure reverse-proxies

LL::NG can protect any Apache hosted application including Apache reverse-proxy mechanism. Example:

PerlOptions +GlobalRequest
PerlRequire /var/lib/lemonldap-ng/handler/
<VirtualHost *:443>
    SSLEngine On
    ... other SSL parameters ...
    PerlInitHandler My::Handler
    ProxyPass /
    ProxyPassReverse /
    ProxyPassReverseCookieDomain /

See mod_proxy and mod_rewrite documentation for more about configuring Apache reverse-proxies.

Such configuration can have some security problems:

  • if a user can access directly to the hidden application, it can bypass LL::NG protection

  • if many hidden applications are on the same private network, if one is corrupted (by SQL injection, or another attack), the hacker will be able to access to other applications without using reverse-proxies so it can bypass LL::NG protection

It is recommended to secure the channel between reverse-proxies and application to be sure that only request coming from the LL::NG protected reverse-proxies are allowed. You can use one or a combination of:

  • firewalls (but be careful if more than 1 server is behind the firewall)

  • server based restriction (like Apache “allow/deny” mechanism)

  • SSL client certificate for the reverse-proxy (see SSLProxy* parameters in mod_ssl documentation)

Configure security settings

Go in Manager, General parameters » Advanced parameters » Security:

  • Username control: Regular expression used to check user login syntax.

  • Avoid browsers to store users password: Enable this option to prevent browsers from prompting users to save passwords.

  • Force authentication: set to ‘On’ to force authentication when user connects to portal, even if he has a valid session.

  • Force authentication interval: time interval (in seconds) when an authentication renewal cannot be forced, used to prevent to loose the current authentication during the main process. If you experience slow network performances, you can increase this value.

  • Encryption key: key used for crypting some data, should not be known by other applications

  • Trusted domains: domains on which the user can be redirected after login on portal.

    • Example:

    • * allows redirections to any external domain (DANGEROUS)

  • Use Safe jail: Set to ‘Off’ to disable Safe jail. Safe module is used to eval expressions in headers, rules, etc. Disabling it can lead to security issues.

  • Avoid assignment in expressions: Set to ‘Off’ to disable syntax checking. Equal sign can be replaced by x3D i.e. “dcx3Dorg”

  • Check XSS Attacks: Set to ‘Off’ to disable XSS checks. XSS checks will still be done with warning in logs, but this will not prevent the process to continue.

  • Required token for forms: To prevent CSRF attack, a token is build for each form. To disable it, set this parameter to ‘Off’ or set a special rule

  • Form timeout: Form token timeout (default to 120 seconds)

  • Use global storage: Local cache is used by default for one time tokens. To use global storage, set it to ‘On’

  • Strict-Transport-Security Max-age: Set STS header max-age if you use SSL only (by example: 15768000)

  • Hashed session storage: when set to “On”, SSO sessions and OIDC tokens are stored with a hashed name, then when parsing storage, nobody can reconver SSO session name or OIDC access_token. Not enabled by default because it breaks exiting OIDC offline sessions. Incompatible with “Proxy” authentication in SOAP mode.

  • CrowdSec Bouncer: Set to ‘On’ to enable CrowdSec Bouncer plugin

  • Brute-Force Attack protection: set to ‘On’ to enable Brute-force protection plugin

  • LWP::UserAgent and SSL options: Insert here options to pass to LWP::UserAgent object (used by SAML or OpenID-Connect to query partners and AuthSSL or AuthBasic handler to request Portal URL). Example: verify_hostname => 0, SSL_verify_mode => 0

  • Content Security Policy: Portal builds dynamically this header. You can modify default values. Browser implementations of formAction directive are inconsistent (e.g. Firefox doesn’t block the redirects whereas Chrome does). Administrators may have to modify formAction value with wildcard likes *.

  • Cross-Origin Resource Sharing: Portal builds those headers. You can modify default values. Administrators may have to modify Access-Control-Allow-Origin value with ‘ ‘.


If URLs are protected with AuthBasic handler, you have to disable CSRF token by setting a special rule based on callers IP address like this :

requireToken => $env->{REMOTE_ADDR} && $env->{REMOTE_ADDR} !~ /^127.0.[1-3].1$/


Enable global storage for one time tokens will downgrade Portal performance!!!

Must ONLY be used with outdated or low performance Load Balancer.


To prevent brute force attack with fail2ban

Edit /etc/fail2ban/jail.conf

enabled = true
port    = http,https
filter  = lemonldap
action   = iptables-multiport[name=lemonldap, port="http,https"]
logpath = /var/log/apache*/error*.log
maxretry = 3

and edit /etc/fail2ban/filter.d/lemonldap.conf

# Fail2Ban configuration file
# Author: Adrien Beudin
# $Revision: 2 $


# Option:  failregex
# Notes.:  regex to match the password failure messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?f{4,6}:)?(?P<host>[\w\-.^_]+)
# Values:  TEXT
failregex = Lemonldap\:\:NG \: .* was not found in LDAP directory \(<HOST>\)
            Lemonldap\:\:NG \: Bad password for .* \(<HOST>\)

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
ignoreregex =

Restart fail2ban

Sessions identifier

You can change the module used for sessions identifier generation. To do, add generateModule key in the configured session backend options.

We recommend to use : Lemonldap::NG::Common::Apache::Session::Generate::SHA256.