Siemens has informed customers that a component of its TeleControl Basic product is affected by several vulnerabilities that can be exploited by an attacker to escalate privileges, bypass authentication, and launch denial-of-service (DoS) attacks.
Siemens’ TeleControl Basic system allows organizations to monitor and control plant processes. The solution can also be used to optimize the operation of municipal facilities, including water treatment, traffic monitoring, and energy distribution. TeleControl Server Basic is the software used for the TeleControl Basic control center.
According to advisories published by Siemens and ICS-CERT, the TeleControl Server Basic system is affected by a total of three vulnerabilities. The most serious of them, tracked as CVE-2018-4836 and rated high severity, allows an attacker with a low privileged account and access to TCP port 8000 to escalate privileges and perform administrative tasks.
Another flaw, CVE-2018-4835, allows an attacker with network access to port 8000 to bypass the system’s authentication mechanism and obtain limited information.
The last security hole, CVE-2018-4837, can be exploited by an attacker with access to the TeleControl web server on TCP ports 80 or 443 to cause the web server to enter a DoS condition. However, Siemens pointed out that the DoS condition does not affect other functionality.
CVE-2018-4835 and CVE-2018-4837 have been classified as medium severity with a CVSS score of 5.3.
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Siemens has patched the vulnerabilities with the release of TeleControl Server Basic 3.1. In addition, the company has identified some workarounds and mitigations that can be used to reduce the risk of attacks.
These include blocking TCP port 8000 using the Windows firewall to mitigate CVE-2018-4835 and CVE-2018-4836, and blocking ports 80 and 443 to prevent attacks involving CVE-2018-4837.
While this is the first advisory released by Siemens and ICS-CERT for a vulnerability specific to TeleControl products, a privilege escalation flaw disclosed in November 2016 had been found to impact TeleControl Server Basic – among many other industrial solutions from Siemens. That security hole was addressed in TeleControl Server Basic with the release of version 3.0.
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