WAGO released new firmware to mitigate an improper resource shutdown or release for its 750 Series, according to a report with ICS-CERT.
Successful exploitation of this remotely exploitable vulnerability, discovered by Younes Dragoni of Nozomi Networks, could allow a denial-of-service condition affecting the ability of the device to establish connections to commissioning and service software tools.
The following versions of 750 series PLC suffer the issue:
• 750-880 firmware version 10 and prior
• 750-881 firmware version 10 and prior
• 750-852 firmware version 10 and prior
• 750-882 firmware version 10 and prior
• 750-885 firmware version 10 and prior
• 750-831 firmware version 10 and prior
• 750-889 firmware version 10 and prior
• 750-829 firmware version 10 and prior
No known public exploits specifically target this vulnerability. However, an attacker with low skill level could leverage the vulnerability.
In the vulnerability, a remote attack may take advantage of an improper implementation of the 3-way handshake during a TCP connection affecting the communications with commission and service tools. Specially crafted packets may also be sent to Port 2455/TCP/IP, used in Codesys management software, which may result in a denial-of-service condition of communications with commissioning and service tools.
CVE-2018-8836 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
The product sees action mainly in the commercial facilities, critical manufacturing, energy, and transportation systems sectors. It also sees use on a global basis. The company has offices in the United States, Germany, Switzerland, Poland, China, and India.
WAGO released new firmware addressing this vulnerability that can be obtained by contacting WAGO support via email.
If updating the firmware is not feasible WAGO recommends users disable the WAGO Service Communication via WBM or limit the access to Ports 6626 and 2455/TCP/IP to trusted devices.
For more information click on WAGO’s security advisory.