Schneider Electric System Monitor XSS affects industrial PCs
Free public brief. The indicators, the detections with Splunk SPL already written (plus Elastic and KQL where they apply), and a Slack alert the next time this touches a vendor you run are in the app — free account, no card.
Reflected XSS in Schneider Electric System Monitor affects all versions of Harmony and Pro-face Industrial PC applications; unpatched systems must be isolated.
Schneider Electric System Monitor application in both Harmony Industrial PC and Pro-face PS5000 Legacy Industrial PC series contains an improper input neutralization vulnerability (CWE-79, Reflected XSS) stemming from vulnerable jQuery versions (1.0.3 to before 3.5.0). The flaw permits remote attackers to execute untrusted code in the context of a user's browser session with a CVSS 3.1 score of 6.9. Exploitation requires user interaction (clicking a malicious link) but carries high attack complexity and wide scope impact, affecting confidentiality severely and integrity slightly. No public exploitation has been reported to CISA to date.
Affected versions include all currently shipped instances of the System Monitor application across both product lines, deployed globally in commercial facilities, critical manufacturing, and energy sectors. Schneider Electric recommends uninstalling the application where not operationally necessary, or implementing strict network segmentation and firewall rules to restrict access to HTTP/HTTPS ports. Organizations unable to remediate immediately should disable the service and isolate systems from untrusted networks, particularly the Internet.
Mentioned in this report
Detection guidance
Reflected XSS Payload in Web Request Query String
Detects script-injection markers in the query string of web requests, the pattern used to exploit reflected XSS (CWE-79) in web-served industrial apps such as Schneider System Monitor. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.
title: Reflected XSS Payload in Web Request Query String
description: 'Detects HTTP requests whose query string carries script-injection markers
(script tags, javascript: URIs, inline event handlers), whether plain or URL-encoded.
Behavioural indicator of reflected XSS exploitation against web-facing applications,
for example the jQuery-based System Monitor on Harmony/Pro-face industrial PCs.
Requires web server logs covering the application''s HTTP/HTTPS ports.'
tags:
- attack.execution
- attack.t1059.007
logsource:
category: webserver
detection:
selection_tag:
cs-uri-query|contains:
- <script
- '%3cscript'
- '%253cscript'
- 'javascript:'
- javascript%3a
selection_handler:
cs-uri-query|contains:
- onerror=
- onload=
- onmouseover=
- onfocus=
cs-uri-query|contains|all:
- '%3c'
- '%3e'
condition: 1 of selection_*
falsepositives:
- Authorized web vulnerability scanners or penetration tests against the application
- Web applications that legitimately accept HTML or script snippets in query parameters,
such as code or CMS editors
level: medium
id: 7914b2c5-54a5-578a-a803-664db42d28f0
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/ics-advisories/icsa-25-203-05
Behavioural rules are generated from public reporting — validate in your environment before deploying.
Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-203-05
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries its extracted indicators, its detections (Splunk SPL already written, plus Elastic and Microsoft KQL where they apply), the actors and CVEs it names as live profiles, and the vendor research on the same campaign — the primary source the news paraphrased, cited and read directly.
It sits in a corpus of 13,854 reports from 146 sources, 614 of them written in the last seven days, and it grows through the day.
A new account starts with three days of all of it, no card, then keeps the government and CERT reporting free. Name the vendors you run and Slack hears about the reports that touch them — about forty a week that are yours, not the four hundred that are not.
Create a free account What it costs