CVSS2
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:A/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
AI Score
Confidence
High
EPSS
Percentile
25.0%
Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition.
Siemens reports this vulnerability affects the following RWG controllers:
3.2.1 ALLOCATION OF RESOURCES WITHOUT LIMITS OR THROTTLING CWE-770
Sending specially crafted ARP packets to an affected device could cause a partial denial-of-service, which may prevent the device from operating normally. A restart is needed to restore normal operations.
CVE-2021-25671 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been calculated; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Siemens reported this vulnerability to CISA.
Siemens recommends users login to the RWG Controller Graphical programming platform, generate a new project file, and download the new project file to the device.
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens operational guidelines for Industrial Security and following the recommendations in the product manuals.
Additional information on industrial security by Siemens can be found at: <https://www.siemens.com/industrialsecurity>.
Please see Siemens Security Advisory SSA-448291 for more information.
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. 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 webpage on us-cert.cisa.gov 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 CISA for tracking and correlation against other incidents.
No known public exploits specifically target this vulnerability. This vulnerability is not exploitable remotely.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-25671
cert-portal.siemens.com/operational-guidelines-industrial-security.pdf
cert-portal.siemens.com/productcert/pdf/ssa-448291.pdf
cert-portal.siemens.com/productcert/pdf/ssa-448291.pdf
cisasurvey.gov1.qualtrics.com/jfe/form/SV_9n4TtB8uttUPaM6?product=https://www.cisa.gov/news-events/ics-advisories/icsa-21-194-14
cwe.mitre.org/data/definitions/770.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
twitter.com/CISAgov
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us-cert.cisa.gov/ics
us-cert.cisa.gov/ics
us-cert.cisa.gov/ics/alerts/ICS-ALERT-10-301-01
us-cert.cisa.gov/ics/recommended-practices
us-cert.cisa.gov/ics/tips/ICS-TIP-12-146-01B
us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
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mailto:?subject=Siemens%20RWG%20Universal%20Controllers&body=www.cisa.gov/news-events/ics-advisories/icsa-21-194-14
CVSS2
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:A/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
ADJACENT
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
AI Score
Confidence
High
EPSS
Percentile
25.0%