LDAP injection: How was it exploited in a Joomla attack?

An 8-year-old flaw in Joomla that permitted an LDAP injection was recently discovered. What is an LDAP injection vulnerability, and how can it be exploited in an attack?

Joomla is a popular content management system that accounts for almost 3% of all websites on the internet, and it has been downloaded over 84 million times. A static analysis organization called Rips Technologies recently found it to be vulnerable to an LDAP injection vulnerability. This vulnerability was in the Joomla code for over eight years, and the company recently released a patch for the web application to remediate the blind LDAP injection.

This type of attack takes place using the login pages of sites that use LDAP for authentication, and it can infiltrate data or applications by abusing entries inserted into the software in an attempt to extract, view or change the data.

An LDAP injection attack, especially a blind one like the one Joomla was vulnerable to, aims to abuse the authentication process of passing credentials to controllers, as an LDAP server stores the username and password of the users in a database. With this particular vulnerability, there's a complete lack of sanitation, enabling an attacker's script to rotate attempts through the login field and slowly extract the credentials of a user -- this is the blind part of the injection, and it is usually aimed at an administrator account to get complete access to the Joomla control panel.

With this vulnerability, an attacker can submit an LDAP injection of query syntax into the login form in an attempt to slowly gain access to the LDAP database one bit request at a time. When the scripted attack runs, it's able to quickly submit multiple login attempts, and it can eventually work through all the possible characters in the credentials until it completes the password. Since this is scripted and aimed at the system's login form, it's able to make quick work of Joomla systems that use LDAP for authentication.

It's probably safe to say that not many Joomla servers use LDAP for authentication, but it's most likely being used somewhere. LDAP is used quite frequently for authentication.

The first thing you should do is review if your site is vulnerable. Anyone running Joomla versions 1.5 through 3.7.5 is vulnerable if they're using LDAP authentication on their unpatched site. However, there was a patch released that specifically addresses this issue, and it can be installed to mitigate this vulnerability.

Using these plug-ins for authentication naturally brings up the topic of using multifactor authentication. Your authentication architecture should no longer rely on systems using single-factor authentication for applications, especially public-facing applications. This process will limit the risk of vulnerabilities or data leaks that can expose data credentials to attackers.

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