Siemens has Mitigation for SIMATIC

Thursday, March 29, 2018 @ 06:03 PM gHale

Siemens has workaround and mitigation plans to offset an improper input validation vulnerability in its SIMATIC PCS 7, SIMATIC WinCC, SIMATIC WinCC Runtime Professional, and SIMATIC NET PC Software, according to a report with ICS-CERT.

Successful exploitation of this remotely exploitable vulnerability, discovered by Vladimir Dashchenko from Kaspersky Lab and independent researcher cdev1, could allow an attacker to cause a denial-of-service condition on the remote and local communication functionality of the affected products. A system reboot is required to recover.

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The vulnerability affects the following SIMATIC products:
• OpenPCS 7 V7.1 and earlier
• OpenPCS 7 V8.0: All versions
• OpenPCS 7 V8.1: All versions
• OpenPCS 7 V8.2: All versions
• OpenPCS 7 V9.0: All versions prior to V9.0 Upd1
• SIMATIC BATCH V7.1 and earlier
• SIMATIC BATCH V8.0: All versions
• SIMATIC BATCH V8.1: All versions
• SIMATIC BATCH V8.2: All versions
• SIMATIC BATCH V9.0: All versions prior to V9.0 SP1
• SIMATIC NET PC-Software: All versions
• SIMATIC PCS 7 V7.1 and earlier
• SIMATIC PCS 7 V8.0: All versions
• SIMATIC PCS 7 V8.1: All versions
• SIMATIC PCS 7 V8.2: All versions
• SIMATIC PCS 7 V9.0: All versions prior to V9.0 SP1
• SIMATIC Route Control V7.1 and earlier
• SIMATIC Route Control V8.0: All versions
• SIMATIC Route Control V8.1: All versions
• SIMATIC Route Control V8.2: All versions
• SIMATIC Route Control V9.0: All versions prior to V9.0 Upd1
• SIMATIC WinCC Runtime Professional: All versions prior to V14 SP1 Upd5
• SIMATIC WinCC 7.2 and earlier
• SIMATIC WinCC 7.3: All versions prior to WinCC 7.3 Upd16
• SIMATIC WinCC 7.4: All versions prior to V7.4 SP1 Upd4

No known public exploits specifically target this vulnerability. However, an attacker with low skill level could leverage the vulnerability.

In the vulnerability, specially crafted messages sent to the RPC service of the affected products could cause a denial-of-service condition on the remote and local communication functionality of the affected products. A reboot of the system is required to recover the remote and local communication functionality.

CVE-2018-4832 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.

The products see use mainly in the chemical, energy, food and agriculture, and water and wastewater systems. They also see action on a global basis.

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
• Upgrade to a newer PCS 7 version
• Ensure SIMATIC WinCC, SIMATIC WinCC Runtime Professional and SIMATIC PCS 7 stations communicate via encrypted channels (i.e., activate feature “Encrypted Communication” in SIMATIC WinCC V7.3 or newer and SIMATIC PCS 7 V8.1 or newer). Enabling “Encrypted Communication” completely mitigates the vulnerability
• Apply cell protection concept
• Use VPN for protecting network communication between cells
• Apply Defense-in-Depth

Siemens released updates for several affected products and recommends users update to the new version. Siemens is preparing further updates and recommends specific countermeasures until patches are available:
• SIMATIC PCS 7 V9.0: Install V9.0 SP1:
Contact local support.
• SIMATIC WinCC Runtime Professional: Update to V14 SP1 Upd5
• SIMATIC WinCC V7.3: Update to WinCC 7.3 Upd16
• SIMATIC WinCC V7.4: Update to V7.4 SP1 Upd4

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. In order to run the devices in a protected IT environment, Siemens particularly recommends that users configure the environment according to Siemens’ Operational Guidelines for Industrial Security and follow the recommendations in the product manuals.

Click here for additional information on industrial security.

For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-348629.



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