Rockwell Automation released patches to mitigate a stack-based buffer overflow in its RSLinx Classic, according to a report with NCCIC.
Successful exploitation of this vulnerability, discovered by Rockwell working with Tenable, could allow a remote attacker to execute arbitrary code on the target device.
PLC communications software, RSLinx Classic Versions 4.10.00 and prior suffer from the vulnerability.
In the vulnerability, there is an input validation issue in a .dll file of RSLinx Classic where the data in a Forward Open service request is passed to a fixed size buffer, allowing an attacker to exploit a stack-based buffer overflow condition.
CVE-2019-6553 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 10.0.
The product sees use mainly in the critical manufacturing, energy, and water and wastewater systems sectors. It also sees action on a global basis.
No known public exploits specifically target this vulnerability. However, an attacker with low skill level could leverage the vulnerability.
Rockwell Automation released patches to address earlier versions of RSLinx Classic including v3.60, v3.70, v3.80, v3.81, v3.90, v4.00.01, v4.10. These patches can be found at Knowledgebase Article ID: 1084828.
Rockwell Automation also said users may disable Port 44818 in RSLinx Classic if it is not utilized during system operation. To disable Port 44818, go to Options in RSLinx Classic. Then in the General tab of the Options pop-up, uncheck the option “Accept UDP Messages on Ethernet Port”.
Port 44818 is needed only when a user wants to utilize unsolicited messages. To check if you are using unsolicited messages, go to the “DDE/OPC” dropdown in RSLinx Classic. Select Topic Configuration and then go to the Data Collection tab in the Topic Configuration pop-up. If the “Unsolicited Messages” checkbox is marked, then Port 44818 is being used in the application. (NOTE: In RSLinx Classic 4.10 or later, “Accept UDP Messages on Ethernet Port” checkbox is unchecked by default.)
For more information click on the Rockwell Automation security advisory.