Siemens Releases 7 Advisories for SIMATIC, SCALANCE Vulnerabilities
15.11.2018 securityweek ICS

Siemens on Tuesday released 7 new advisories to inform customers of potentially serious vulnerabilities affecting various SIMATIC and SCALANCE products. Patches and/or mitigations are available for all impacted products.

According to the industrial giant, members of China’s CNCERT/CC discovered two high severity flaws in SIMATIC S7 CPUs. An attacker who has access to impacted devices on TCP port 102 via Ethernet, MPI or Profibus can cause a denial-of-service (DoS) condition by sending specially crafted packets.

Exploitation of the flaw, which requires no user interaction, could result in the targeted device going into defect mode until it’s manually rebooted.

While DoS vulnerabilities are often less serious from an IT perspective, in the case of industrial control systems (ICS), where availability is critical, these types of flaws can have a severe impact, including physical damage to equipment and incidents that could lead to loss of human life.

Siemens also told customers that some SIMATIC human-machine interfaces (HMIs) are affected by a high severity flaw that can be exploited by an unauthenticated attacker to download arbitrary files from a device without any user interaction. A less serious vulnerability in the same products allows attackers to redirect targeted users to arbitrary websites by getting them to click on a malicious link.

These products also contain a medium severity HTTP header injection vulnerability, Siemens said.

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A researcher from industrial cybersecurity firm Applied Risk discovered that Siemens’ SCALANCE S firewalls are affected by a cross-site scripting (XSS) vulnerability that can be exploited to bypass important security measures. The targeted user needs to be authenticated with administrator privileges and click on a specially crafted link.

Siemens has rated this vulnerability as “medium severity” with a CVSSv3 score of 4.7. Applied Risk, on the other hand, believes this is a “high severity” issue and assigned it a CVSSv3 score of 8.2.

Another advisory published by Siemens this week describes an authentication bypass vulnerability in the SIMATIC IT Production Suite, an IT solution that bridges control systems and business systems. The vendor noted that exploitation requires a valid username and access to the network, but no privileges or interaction are needed to conduct an attack.

The remaining advisories published by Siemens describe medium severity issues, including a DoS vulnerability in SIMATIC S7 CPUs, and a SIMATIC STEP7 flaw that can be exploited to obtain passwords stored in a project.

Siemens is not aware of any instances where these vulnerabilities have been exploited for malicious purposes.

ICS-CERT has also published advisories this week for these and other vulnerabilities affecting products from Siemens.