Siemens SIPROTEC 5 and DIGSI 5

1. EXECUTIVE SUMMARY

• CVSS v3 7.5
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Siemens
• Equipment: SIPROTEC 5 and DIGISI 5
• Vulnerabilities: Improper Input Validation

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow a denial-of-service condition and limited control of file upload, download, and delete functions.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following SIPROTEC 5 and DIGSI 5 products:

• SIPROTEC 5 (All versions prior to v7.90) with CPU variants CP300 and CP100 and the respective Ethernet communication modules listed below:
  • 6MD85
  • 6MD86
  • 6MD89
  • 7UM85
  • 7SA87
  • 7SD87
  • 7SL87
  • 7VK87
  • 7SA82
  • 7SA86
  • 7SD82
  • 7SD86
  • 7SL82
  • 7SL86
  • 7SJ86
  • 7SK82
  • 7SK85
  • 7SJ82
  • 7SJ85
  • 7UT82
  • 7UT85
  • 7UT86
  • 7UT87
  • 7VE85
  • All types not listed above
    • All versions
• SIPTROTEC 5 with CPU variants CP200 and the respective Ethernet communication modules
  • All versions
• DIGSI 5
  • All Versions prior to v7.90

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER INPUT VALIDATION CWE-20

A remote attacker could use specially crafted packets sent to Port 443/TCP to upload, download, or delete files in certain parts of the file system.

CVE-2019-10930 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).

3.2.2    IMPROPER INPUT VALIDATION CWE-20

Specially crafted packets sent to Port 443/TCP could cause a denial-of-service condition.

CVE-2019-10931 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Energy
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Pierre Capillon, Nicolas Iooss, and Jean-Baptiste Galet from Agence Nationale de la Sécurité des Systèmes d’Information (ANSSI) reported these vulnerabilities to Siemens.

4. MITIGATIONS

Siemens recommends users upgrade to V7.90 where available and apply the following specific mitigations:

SIPROTEC 5 device types 6MD85, 6MD86, 6MD89, 7UM85, 7SA87, 7SD87, 7SL87, 7VK87, 7SA82, 7SA86, 7SD82, 7SD86, 7SL82, 7SL86, 7SJ86, 7SK82, 7SK85, 7SJ82, 7SJ85, 7UT82, 7UT85, 7UT86, 7UT87 and 7VE85 with CPU variants CP300 and CP100 and the respective Ethernet communication modules:

• Update to firmware version V7.90. Search for ‘SIPROTEC 5 – DIGSI Device Drivers V7.90’ on the Siemens Industry Online Support site. Firmware version V7.90 for the communication modules can also be found on each device specific download page. Applying the update causes the device / module to go through a single restart cycle.

https://support.industry.siemens.com/cs/ww/en/

DIGSI 5 engineering software:

• Update to DIGSI 5 V7.90 and activate the client authorization feature:

https://support.industry.siemens.com/cs/us/en/view/109767686

All other SIPROTEC 5 device types with CPU variants CP300, CP200, and CP100 and the respective Ethernet communication modules:

• Block access to Port 443/TCP e.g. with an external firewall.

For more information on this vulnerability and associated software updates, please see Siemens security advisory SSA-899560 on their website: https://www.siemens.com/cert/advisories

NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS-CERT website in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.

No known public exploits specifically target these vulnerabilities.