SSA-344238: TCP Session Hijacking Vulnerability in Siemens Energy PLUSCONTROL 1st Gen Devices
Publication Date:
2021-03-09
Last Update:
2021-03-09
Current Version:
V1.0
CVSS v3.1 Base Score:
6.5
SUMMARY
PLUSCONTROL 1st Gen devices are affected by a vulnerability as initially reported in SSA-362164 for the Mentor Nucleus TCP/IP stack. The vulnerability could allow an attacker located in the same network to hijack or terminate TCP/IP sessions of a vulnerable device.
Siemens Energy recommends specific countermeasures for use cases of the affected product.
AFFECTED PRODUCTS AND SOLUTION
Affected Product and Versions
Remediation
PLUSCONTROL 1st Gen:
All versions
See recommendations from section Workarounds and Mitigations
WORKAROUNDS AND MITIGATIONS
Siemens has identified the following specific workarounds and mitigations that customers can apply to reduce the risk:
PLUSCONTROL devices are typically located in a separate LAN segment of energy transmission solutions, where an attacker could use this vulnerability to disrupt SER messages or Trace functionalities. Therefore, review the status of the defense in depth recommendations that apply to your specific deployment and align as needed. Especially the measures on the network layer to prevent accessibility from other network segments.
GENERAL SECURITY RECOMMENDATIONS
Operators of critical power systems (e.g. TSOs or DSOs) worldwide are usually required by regulations to build resilience into the power grids by applying multi-level redundant secondary protection schemes. It is therefore recommended that the operators check whether appropriate resilient protection measures are in place. The risk of cyber incidents impacting the grid’s reliability can thus be minimized by virtue of the grid design.
Siemens strongly recommends applying the provided security updates using the corresponding tooling and documented procedures made available with the product. If supported by the product, an automated means to apply the security updates across multiple product instances may be used. Siemens strongly recommends prior validation of any security update before being applied, and supervision by trained staff of the update process in the target environment.
As a general security measure Siemens strongly recommends to protect network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN). It is advised to configure the environment according to our operational guidelines in order to run the devices in a protected IT environment.
PRODUCT DESCRIPTION
PLUSCONTROL products from Siemens Energy are control devices for high power energy transmission with modular multilevel converters.
VULNERABILITY CLASSIFICATION
The vulnerability classification has been performed by using the CVSS scoring system in version 3.1
(CVSS v3.1) (https://www.first.org/cvss ). The CVSS environmental score is specific to the customer’s
environment and will impact the overall CVSS score. The environmental score should therefore be
individually defined by the customer to accomplish final scoring.
An additional classification has been performed using the CWE classification, a community-developed
list of common software security weaknesses. This serves as a common language and as a baseline for
weakness identification, mitigation, and prevention efforts. A detailed list of CWE classes can be found
at: https://cwe.mitre.org/ .
Vulnerability CVE-2020-28388
Initial Sequence Numbers (ISNs) for TCP connections are derived from an insufficiently random source. As a result, the ISN of current and future TCP connections could be predictable. An attacker could hijack existing sessions or spoof future ones.
CVSS v3.1 Base Score
6.5
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:O/RC:C
CWE:
CWE-342: Predictable Exact Value from Previous Values
ADDITIONAL INFORMATION
For more details regarding this vulnerability CVE-2020-28388 refer to
For further inquiries on security vulnerabilities in Siemens products and solutions, please contact
the Siemens ProductCERT:
https://www.siemens.com/cert/advisories
HISTORY DATA
V1.0 (2021-03-09): Publication Date
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