Siemens Clears Hole in SIPROTEC 5 Devices

Apr 25, 2023 | Incidents

Siemens has updates and mitigations available to handle a NULL pointer dereference vulnerability in its SIPROTEC 5 devices, according to a report with CISA.

Successful exploitation of this remotely exploitable vulnerability, discovered by Turek Witold from Polskie Sieci Elektroenergetyczne S.A, could cause a denial-of-service condition of the target device.

In the vulnerability, affected devices lack proper validation of HTTP request parameters of the hosted web service. An unauthenticated remote attacker could send specially crafted packets that could cause a denial-of-service condition of the target device.

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CVE-2023-28766 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.

The following software suffers from the issue:

Schneider Bold
  • SIPROTEC 5 6MD85 (CP200): All versions (v)
  • SIPROTEC 5 6MD85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 6MD86 (CP200): All versions
  • SIPROTEC 5 6MD86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 6MD89 (CP300): All versions
  • SIPROTEC 5 6MU85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7KE85 (CP200): All versions
  • SIPROTEC 5 7KE85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SA82 (CP100): All versions
  • SIPROTEC 5 7SA82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SA84 (CP200): All versions
  • SIPROTEC 5 7SA86 (CP200): All versions
  • SIPROTEC 5 7SA86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SA87 (CP200): All versions
  • SIPROTEC 5 7SA87 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SD82 (CP100): All versions
  • SIPROTEC 5 7SD82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SD84 (CP200): All versions
  • SIPROTEC 5 7SD86 (CP200): All versions
  • SIPROTEC 5 7SD86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SD87 (CP200): All versions
  • SIPROTEC 5 7SD87 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SJ81 (CP100): All versions
  • SIPROTEC 5 7SJ81 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SJ82 (CP100): All versions
  • SIPROTEC 5 7SJ82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SJ85 (CP200): All versions
  • SIPROTEC 5 7SJ85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SJ86 (CP200): All versions
  • SIPROTEC 5 7SJ86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SK82 (CP100): All versions
  • SIPROTEC 5 7SK82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SK85 (CP200): All versions
  • SIPROTEC 5 7SK85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SL82 (CP100): All versions
  • SIPROTEC 5 7SL82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SL86 (CP200): All versions
  • SIPROTEC 5 7SL86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SL87 (CP200): All versions
  • SIPROTEC 5 7SL87 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SS85 (CP200): All versions
  • SIPROTEC 5 7SS85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7ST85 (CP200): All versions
  • SIPROTEC 5 7ST85 (CP300): All versions
  • SIPROTEC 5 7ST86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7SX82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7SX85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7UM85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7UT82 (CP100): All versions
  • SIPROTEC 5 7UT82 (CP150): All versions prior to v9.40
  • SIPROTEC 5 7UT85 (CP200): All versions
  • SIPROTEC 5 7UT85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7UT86 (CP200): All versions
  • SIPROTEC 5 7UT86 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7UT87 (CP200): All versions
  • SIPROTEC 5 7UT87 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7VE85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7VK87 (CP200): All versions
  • SIPROTEC 5 7VK87 (CP300): All versions prior to v9.40
  • SIPROTEC 5 7VU85 (CP300): All versions prior to v9.40
  • SIPROTEC 5 Communication Module ETH-BA-2EL: All versions prior to v9.40
  • SIPROTEC 5 Communication Module ETH-BB-2FO: All versions prior to v9.40
  • SIPROTEC 5 Communication Module ETH-BD-2FO: All versions prior to v9.40
  • SIPROTEC 5 Compact 7SX800 (CP050): All versions prior to v9.40

The product sees use in multiple industrial sectors, and on a global basis.

No known public exploits specifically target this vulnerability. However, an attacker could leverage this low complexity vulnerability.

Siemens released fixes for several affected products and recommends updating to the latest versions. Siemens recommends specific countermeasures for products where updates are not, or not yet, available:

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk: Block access to port 4443/TCP e.g. with an external firewall.

Worldwide regulations for critical power systems (e.g. TSOs or DSOs) usually require multi-level redundant secondary protection schemes to build resilience into power grids. It is recommended that operators check whether appropriate resilient protection measures are in place to minimize the risk of cyber incidents impacting the grid’s reliability.

Siemens recommends operators:

  • Apply provided security updates using the corresponding tooling and documented procedures made available with the product.
  • Automatically apply security updates across multiple product instances if automation is supported by the product.
  • Validate any security update before being applied. It is recommended to perform the update process under the supervision of trained staff in the target environment.
  • Protect network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN) as a general security measure.

In order to run the devices in a protected IT environment, it is advised to configure the environment according to Siemens operational guidelines.

Recommended security guidelines can be found at Siemens’ grid security page.

For more information, click on Siemens security advisory SSA-322980.

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