4 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:S/C:N/I:N/A:P
4.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
5.3 Medium
AI Score
Confidence
High
0.003 Low
EPSS
Percentile
69.3%
CVSS v3 4.9
**ATTENTION:**Exploitable remotely/low skill level to exploit
**Vendor:**Siemens
**Equipment:**SIMATIC PCS 7
**Vulnerabilities:**Improper Input Validation
This updated advisory is a follow-up to the original advisory titled ICSA-17-306-01 Siemens SIMATIC PCS 7 that was published November 2, 2017, on the NCCIC/ICS-CERT website.
Successful exploitation of this vulnerability could allow a remote authenticated attacker to crash services on the devices.
The following versions of SIMATIC PCS 7, a distributed control system, are affected:
--------- Begin Update 1 Part 1 of 2 --------
--------- End Update 1 Part 1 of 2 ----------
An authenticated remote attacker who is a member of the administrators group to crash services by sending specially-crafted messages to the DCOM interface.
CVE-2017-6867 has been assigned to this vulnerability. A CVSS v3 base score of 4.9 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
Sergey Temnikov and Vladimir Dashchenko of Kaspersky Labs reported the vulnerability to Siemens.
Siemens has released the following updates:
<https://support.industry.siemens.com/cs/ww/en/view/109746452>
--------- Begin Update A Part 2 of 2 --------
--------- End Update A Part 2 of 2 ----------
Siemens recommends that affected users apply the following mitigations:
Siemens also strongly recommends that users protect network access to the SIMATIC PCS 7 with appropriate mechanisms by configuring the environment according to operation guidelines that can be found at:
<https://support.industry.siemens.com/cs/ww/en/view/60119725>
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-523365 at the following location:
<http://www.siemens.com/cert/en/cert-security-advisories.htm>
NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
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 this vulnerability.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-6867
www.siemens.com/cert/en/cert-security-advisories.htm
cwe.mitre.org/data/definitions/20.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109746452
support.industry.siemens.com/cs/ww/en/view/60119725
twitter.com/CISAgov
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4 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:S/C:N/I:N/A:P
4.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
5.3 Medium
AI Score
Confidence
High
0.003 Low
EPSS
Percentile
69.3%