The developers of the popular vBulletin commercial Internet forum software are investigating a potential exploit and advised users to delete the "install" directory from their deployments as a precaution.
"A potential exploit vector has been found in the vBulletin 4.1+ and 5+ installation directories," Wayne Luke, technical support lead at vBulletin Solutions, the company that develops the software, announced this week on the vBulletin community forum. "Our developers are investigating this issue at this time. If deemed necessary we will release the necessary patches."
Luke advised users to delete the 'install' directory from their vBulletin installations in order to mitigate the issue that hasn't yet been disclosed. The directory that should be deleted is "/install" for vBulletin 4.1.x versions and "/core/install" for the 5.x versions.
This directory normally contains the scripts and files used during the original installation process and subsequent upgrades.
In the "Cleaning up after Install" section of the vBulletin manual users are advised to delete all files and subdirectories from the "install" directory as a security precaution. However, they are not advised to delete the directory itself.
It's not clear what the exploit currently being investigated would allow potential attackers to do, but the fact that it prompted an advance warning from the developers suggests that it might have serious implications.
Luke declined to disclose information about the nature of the exploit.
"I am sorry but in the interest of security for our customers, we can not discuss this issue at this time," he said Thursday via email.
"Going back to our logs, we dont see any specific scans for /core/install, but we see constant discovery requests for /install," said Daniel Cid, chief security officer at Sucuri, a company that provides website security monitoring and malware clean-up services, in a blog post. "We dont yet know if that is related to vBulletin or other CMSs [content management systems]."
Attackers are constantly trying to exploit vulnerabilities in popular content management systems in order to break into websites, and while vBulletin does not power as many websites as WordPress, Joomla or some other general-purpose CMS software, it is one of the most popular applications for setting up Internet discussion forums.
According to vBulletin Solutions, over 100,000 community websites are running on vBulletin, including some operated by Zynga, Electronic Arts, Sony Pictures, NASA, Valve Corporation and other well known companies.
In July, hackers broke into UbuntuForums.org, a community website for the Ubuntu Linux distribution with over 1.8 million registered accounts, and managed to access information about users, including email addresses and password hashes. The site was using vBulletin.
"In summary, the root cause was a combination of a compromised individual account and the configuration settings in vBulletin, the Forums application software," Canonical, the company that operates the site, said in a blog post following the incident.