Siemens has workarounds and mitigations to handle a uncontrolled resource consumption vulnerability in its SIMATIC WinAC RTX (F) 2010, according to a report with CISA.
Successful exploitation of this remotely exploitable vulnerability, discovered by Tal Keren from Claroty, could allow an attacker to perform a denial-of-service attack that could compromise the availability of the service provided by the software.
A software controller for PC-based automation solutions, all versions of SIMATIC WinAC RTX (F) 2010 suffer from the issue. In the vulnerability, an unauthenticated attacker sending a large HTTP request to the host where WinAC RTX is running may trigger a denial-of-service condition.
CVE-2019-13921 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
The product sees use mainly in the critical manufacturing sector. 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 has identified the following specific workarounds and mitigations users can apply to reduce the risk:
• Restrict network access to the host containing the affected service
• If the service is not used as a server, configure Windows Firewall to disable communications on the port of the vulnerable service
As a general security measure, Siemens strongly 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 more detailed mitigation instructions, see Siemens security advisory SSA-878278.