9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10 High
AI Score
Confidence
High
7.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
0.974 High
EPSS
Percentile
99.9%
This updated advisory is a follow-up to the advisory update titled ICSA-22-167-06 Siemens Apache HTTP Server that was published June 16, 2022, to the ICS webpage on www.cisa.gov/uscert.
Successful exploitation of these vulnerabilities could allow an attacker to access or modify resources, crash the device, or achieve code execution.
The following Siemens products are affected:
--------- Begin Update A part 1 of 3 ---------
--------- End Update A part 1 of 3 ---------
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server v2.4.48 and earlier.
CVE-2021-34798 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party and external modules may. This issue affects Apache HTTP Server v2.4.48 and earlier.
CVE-2021-39275 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
A crafted request uri-path can cause mod_proxy to forward the request to an origin server chosen by the remote user. This issue affects Apache HTTP Server v2.4.48 and earlier.
CVE-2021-40438 has been assigned to this vulnerability. A CVSS v3 base score of 9.0 has been assigned; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).
Siemens reported these vulnerabilities to CISA.
Siemens recommends updating the following to the latest version:
--------- Begin Update A part 2 of 3 ---------
--------- End Update A part 2 of 3 ---------
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
As a general security measure, Siemens 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 Siemensโ operational guidelines for industrial security and following recommendations in the product manuals.
Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage.
--------- Begin Update A part 3 of 3 ---------
For more information see Siemens Security Advisory SSA-685781 in HTML or CSA
--------- End Update A part 3 of 3 ---------
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 cisa.gov/ics 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 cisa.gov/ics in the Technical Information Paper, ICS-TIP-12-146-01BโTargeted 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 these vulnerabilities.
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-34798
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-39275
web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-40438
cert-portal.siemens.com/productcert/csaf/ssa-685781.json
cert-portal.siemens.com/productcert/html/ssa-685781.html
cisa.gov/ics
cisa.gov/ics
cwe.mitre.org/data/definitions/476.html
cwe.mitre.org/data/definitions/787.html
cwe.mitre.org/data/definitions/918.html
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
support.industry.siemens.com/cs/ww/en/view/109811169
support.industry.siemens.com/cs/ww/en/view/109813788
twitter.com/CISAgov
twitter.com/intent/tweet?text=Siemens%20Apache%20HTTP%20Server%20%28Update%20A%29+https://www.cisa.gov/news-events/ics-advisories/icsa-22-167-06
www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01
www.cisa.gov/uscert/ics/recommended-practices
www.cisa.gov/uscert/ics/tips/ICS-TIP-12-146-01B
www.cisa.gov/uscert/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf
www.dhs.gov
www.dhs.gov/foia
www.dhs.gov/performance-financial-reports
www.facebook.com/CISA
www.facebook.com/sharer/sharer.php?u=https://www.cisa.gov/news-events/ics-advisories/icsa-22-167-06&title=Siemens%20Apache%20HTTP%20Server%20%28Update%20A%29
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
www.instagram.com/cisagov
www.linkedin.com/company/cybersecurity-and-infrastructure-security-agency
www.linkedin.com/sharing/share-offsite/?url=https://www.cisa.gov/news-events/ics-advisories/icsa-22-167-06
www.oig.dhs.gov/
www.siemens.com/cert/operational-guidelines-industrial-security
www.siemens.com/industrialsecurity
www.surveymonkey.com/r/CISA-cyber-survey?product=https://www.cisa.gov/news-events/ics-advisories/icsa-22-167-06
www.usa.gov/
www.whitehouse.gov/
www.youtube.com/@cisagov
mailto:?subject=Siemens%20Apache%20HTTP%20Server%20%28Update%20A%29&body=www.cisa.gov/news-events/ics-advisories/icsa-22-167-06
9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10 High
AI Score
Confidence
High
7.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
0.974 High
EPSS
Percentile
99.9%