After being notified by researchers at Sucuri, the developers of the Akeeba backup extension for Joomla fixed a vulnerability that can be leveraged to gain access to website backups.
Akeeba Backup for Joomla, which has been downloaded more than 8 million times, is an open-source extension that can be used to create complete or partial backups for websites powered by Joomla. The security hole found by Sucuri can be exploited download the backups, which can contain database passwords, user credentials with hashed passwords, and password-reset tokens (also hashed).
The vulnerability, which affects the JSON remote API that’s available when users enable front-end backups, has been rated by the security firm as low risk because it’s very difficult to exploit. This is most likely why it remained undetected for four years.
Marc-Alexandre Montpas, the Sucuri researcher who discovered the flaw, noted that only an experienced cryptanalyst can understand how the attack works.
“The extension contains a full-blown JSON API which allows its users to easily set-up some remote automatic backup system. It also implements some advanced encryption mechanism (using AES with the Cipher-block chaining (CBC) and Counter (CTR) encryption modes) intended to provide a safe way to prevent eavesdroppers from stealing backup for websites that does not have a SSL certificate,” Montpas explained in a blog post.
“The problem was located in the way they handled user authentication when an encrypted request was received. The extension would simply not go through the authentication routine based on the assumption that if the user was able to send a valid encrypted JSON payload, he knows the website’s secret key, and if he knows that piece of information it is a legit user,” he added.
According to the researcher, an attacker could communicate with the API just like a legitimate user after obtaining another key by brute-forcing valid encrypted JSON payloads one character at a time. Being able to communicate with the API gives the attacker the ability to bypass cryptographic protections for password reset requests.
Akeeba developers have clarified that the vulnerability can’t be exploited to directly hack a website.
“At worst, a successful attacker would get access to your backups. They would not be able to write anything to your site’s disk or database, therefore they can’t directly hack your site,” they wrote in an advisory published last week. “A determined, well-staffed and well-funded opponent (criminal network, enterprise actor or state actor) could use this information to manually attempt to detect a different attack vector to hack your site. In so many words, no, it’s not realistic to say that your site is in danger.”
Users are advised to update their installations to Akeeba Backup for Joomla 3.11.x. The updates can be installed by accessing the “Updates” menu in the extensions manager.
This isn’t the first time Sucuri researchers uncover vulnerabilities in popular extensions. Over the past months, they’ve uncovered flaws in several WordPress plugins, including MailPoet, Custom Contact Forms and WordPress Mobile Pack.
