# Schneider Electric System Monitor XSS affects industrial PCs

Published: 2025-07-22 · Severity: high · Sectors: manufacturing, energy, infrastructure
Canonical: https://vorant.io/reports/9fa2664d-3f3f-566e-bf45-e0826e6439ac/schneider-electric-system-monitor-xss-affects-industrial-pcs

> 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

- Vulnerabilities: CVE-2020-11023 (KEV)

## Detection guidance (public sample)

### Reflected XSS Payload in Web Request Query String

ATT&CK: T1059.007

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.

```yaml
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

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