vBulletin is prone to a remote code-execution vulnerability. Attackers can exploit this issue to execute arbitrary code within the context of the affected application. Failed exploit attempts will likely cause a denial-of-service condition. vBulletin versions 5.5.4 and prior are vulnerable.
Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, run applications with the minimal amount of privileges required for functionality.
Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity. This includes but is not limited to requests that include NOP sleds and unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from a successful exploit.
Do not accept or execute files from untrusted or unknown sources.
To limit exposure to these and other latent vulnerabilities, never handle files that originate from unfamiliar or untrusted sources.
Do not follow links provided by unknown or untrusted sources.
To reduce the likelihood of attacks, never visit sites of questionable integrity or follow links provided by unfamiliar or untrusted sources.
Implement multiple redundant layers of security.
As an added precaution, deploy memory-protection schemes (such as nonexecutable stack/heap configuration and randomly mapped memory segments). This may complicate exploits of memory-corruption vulnerabilities.
Updates are available. Please see the references or vendor advisory for more information.