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AUSCERT External Security Bulletin Redistribution
ESB-2020.2294
Advisory (icsa-20-184-01) Nortek Linear eMerge 50P/5000P
3 July 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Nortek Linear eMerge
Publisher: ICSA
Operating System: Network Appliance
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Cross-site Request Forgery -- Remote with User Interaction
Unauthorised Access -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2019-7270 CVE-2019-7269 CVE-2019-7268
CVE-2019-7267 CVE-2019-7266
Original Bulletin:
https://www.us-cert.gov/ics/advisories/icsa-20-184-01
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ICS Advisory (ICSA-20-184-01)
Nortek Linear eMerge 50P/5000P
Original release date: July 02, 2020
Legal Notice
All information products included in https://us-cert.gov/ics are provided"as
is" for informational purposes only. The Department of Homeland Security (DHS)
does not provide any warranties of any kind regarding any information contained
within. DHS does not endorse any commercial product or service, referenced in
this product or otherwise. Further dissemination of this product is governed by
the Traffic Light Protocol (TLP) marking in the header. For more information
about TLP, see https://www.us-cert.gov/tlp/ .
1. EXECUTIVE SUMMARY
o CVSS v3 10.0
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Nortek
o Equipment: Linear eMerge 50P/5000P
o Vulnerabilities: Path Traversal, Command Injection, Unrestricted Upload of
File with Dangerous Type, Cross-site Request Forgery, Improper
Authentication
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow a remote attacker
to gain full system access.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Linear eMerge products are affected:
o Linear eMerge 50P/5000P Versions 4.6.07 (revision 79330) and prior
3.2 VULNERABILITY OVERVIEW
3.2.1 PATH TRAVERSAL CWE-35
The software uses external input to construct a pathname that should be within
a restricted directory, but does not properly neutralize sequences such as "../
" that can resolve to a location that is outside of that directory. This allows
attackers to traverse the file system to access files or directories that are
outside of the restricted directory.
CVE-2019-7267 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 ).
3.2.2 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS USED IN A COMMAND ('COMMAND
INJECTION') CWE-77
The application constructs an OS command using externally influenced input from
an upstream component, but incorrectly neutralizes special elements that could
modify the intended OS command when it is sent to a downstream component. This
could allow attackers to execute dangerous commands directly on the operating
system.
CVE-2019-7269 has been assigned to this vulnerability. A CVSS v3 base score of
10.0 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:C/C:H
/I:H/A:H ).
3.2.3 UNRESTRICTED UPLOAD OF FILE WITH DANGEROUS TYPE CWE-434
The vulnerability exists due to the absence of file extension validation when
uploading files through the firmware upgrade upload script. A remote,
unauthenticated attacker can upload files with arbitrary extensions into a
directory within the application's web root and execute them with privileges of
the web server.
CVE-2019-7268 has been assigned to this vulnerability. A CVSS v3 base score of
10.0 has been assigned; the CVSS vector string is ( AV:N/AC:L/PR:N/UI:N/S:C/C:H
/I:H/A:H ).
3.2.4 CROSS-SITE REQUEST FORGERY (CSRF) CWE-352
The affected application allows users to perform certain actions via HTTP
requests without performing any validity checks to verify the requests. This
can be exploited to perform certain actions with administrative privileges if a
logged-in user visits a malicious website.
CVE-2019-7270 has been assigned to this vulnerability. A CVSS v3 base score of
5.0 has been assigned; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:R/S:U/C:L/
I:L/A:L ).
3.2.5 IMPROPER AUTHENTICATION CWE-287
The vulnerability exists due to insufficient validation of input data in
authentication mechanism. A remote attacker can send a specially crafted HTTP
request abusing the Cookie header value traversing to an arbitrary session file
that bypasses authentication checks and gains unauthorized access to the
application.
CVE-2019-7266 has been assigned to this vulnerability. A CVSS v3 base score of
8.1 has been assigned; the CVSS vector string is ( AV:N/AC:H/PR:N/UI:N/S:U/C:H/
I:H/A:H ).
3.3 BACKGROUND
o CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Italy
3.4 RESEARCHER
Gjoko of Applied Risk reported these vulnerabilities to CISA.
4. MITIGATIONS
Nortek has released v32-09a. For more information please contact Nortek
customer support .
CISA recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure that they are not accessible from the Internet .
o Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
o When remote access is required, use secure methods, such as Virtual Private
Networks (VPNs), recognizing that VPNs may have vulnerabilities and should
be updated to the most current version available. Also recognize that VPN
is only as secure as the connected devices.
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.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.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 these vulnerabilities.
For any questions related to this report, please contact the CISA at:
Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870
CISA continuously strives to improve its products and services. You can help by
choosing one of the links below to provide feedback about this product.
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