New exploit code has led researchers to reclassify a security threat aimed at the Linux enterprise search tool Apache Solr to “high severity status.”

Affected hardware could be hit with remote code execution (RCE) attacks that take advantage of a default configuration vulnerability, according to a blog post from Tenable.

Solr — which was originally designed to help those visiting the popular tech news site CNET look up information — has been run for the past 13 years by open-source organization Apache Software Foundation, which has continued to enhance its capabilities for other organizations. The exploit code discovery follows initial reports of a bug this past July, which were not considered as serious.

How the Solr Vulnerability Became a Critical Risk

Researchers originally believed the security issue with Solr would only allow cybercriminals and other third parties to access monitoring data. Further investigation showed, however, that using proof-of-concept code could allow malware to be uploaded and run on a Solr server, based on a hole in the 8983 port.

Although Windows users are reportedly not affected, the bug could be a powerful tool for misuse by anyone with network access to a Solr server and Java Management Extensions.

The Solr team issued a warning late last week, following the publication of revised proof-of-concept exploit code on the popular repository GitHub. Part of the concern stems from the fact that Apache Solr uses large volumes of compute power, which may be of interest to cryptocurrency miners and other cybercriminals.

Reducing the Risk of RCE Attacks

The Solr advisory suggested that anyone worried about being hit by an attack based on the exploit code could avoid the risk by using the “False” parameter for ENABLE_REMOTE_JMX_OPTS in their solr.in.sh file settings. The Solr team also suggested users ensure they are updated to version 8.3, though the Tenable post suggested many versions, including that one, were vulnerable to the bug.

Another way to stay safe from this and other RCE attacks is to invest in vulnerability management solutions or services that can identify, prioritize and remediate exploit code and other flaws in commonly used software applications.