Siemens has a new version out to handle a resource exhaustion vulnerability in its SIMATIC S7, according to a report with NCCIC.
Successful exploitation of this remotely exploitable vulnerability, discovered by Younes Dragoni of Nozomi Networks, could result in a denial-of-service condition that could result in a loss of availability of the affected device.
Siemens said the following SIMATIC S7 products are affected:
• SIMATIC S7-1200: All versions
• SIMATIC S7-1500: All versions prior to 2.6
In the vulnerability, an attacker could exhaust the available connection pool of an affected device by opening a sufficient number of connections to the device. Successful exploitation requires an attacker to be able to send packets to Port 102/TCP of the affected device.
CVE-2018-13815 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 5.3.
The product sees use in the chemical, critical manufacturing, energy, food and agriculture, 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.
Siemens recommends users of SIMATIC S7-1500 update to Version 2.6.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
• Protect network access to Port 102/TCP of affected devices
• Apply cell-protection concept
• Apply defense-in-depth
As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security, and following the recommendations in the product manuals.
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For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-584286.