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Serious Flaws in CODESYS Products Expose Industrial Systems to Remote Attacks

Several critical and high-severity vulnerabilities have been found recently in widely used CODESYS industrial products made by Germany-based 3S-Smart Software Solutions.

The U.S. Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency (CISA) last week published several advisories describing vulnerabilities in CODESYS products, many of which can be exploited remotely for arbitrary code execution, denial-of-service (DoS) attacks, and other purposes. 3S-Smart published its own advisories for most of the security bugs in late July.

The affected software is used by many third-party vendors for hundreds of industrial products.

The most recent advisory from CODESYS, published on September 12, describes a critical stack-based buffer overflow in the CODESYS ENI server, which helps manage objects in a CODESYS project. This flaw, not covered by CISA’s advisories, can be exploited remotely by an attacker with low skills for arbitrary code execution or DoS attacks by sending specially crafted requests to the targeted server.

Another critical vulnerability was found in a gateway component of the CODESYS V3 automation platform. Impacted products include CODESYS Control, Gateway V3 and V3 Development System. This weakness allows a remote attacker to take over or close existing communication channels. A different issue in the same component allows a remote attacker to cause a DoS condition by sending specially crafted requests.

The web server component in CODESYS V3 is affected by a critical vulnerability that can be used to access files, cause the server to crash, or execute arbitrary code using specially crafted requests. This flaw impacts Control, HMI V3 and several toolkits.

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Another V3 component, designed for user management, is affected by a high-severity issue that allows an attacker with access to PLC traffic to obtain user credentials, which are not protected properly during transport. The same component can incorrectly grant access to files and applications to authenticated users who may normally not have permission to access them.

There is also a serious vulnerability in CODESYS V3 products that use a communication server for communication with clients such as the Development System. This security bug allows specially crafted requests to cause a DoS condition.

The CODESYS Development System, a programming tool for industrial controllers, is affected by a vulnerability that can be exploited locally to deliver malicious content via documentation for CODESYS libraries.

3S-Smart says it’s not aware of any public exploits targeting these vulnerabilities, but for at least one of the security holes there is enough publicly available information for an exploit to be developed.

All of these vulnerabilities have been fixed with software updates, except for one, which will be patched with an update expected for February 2020.

Several external researchers have been credited by 3S-Smart for responsibly disclosing these vulnerabilities.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.