CVE-2024-5624: B&R APROL Shift Logbook XSS Vulnerability

CVE-2024-5624 Overview

CVE-2024-5624 is a reflected Cross-Site Scripting (XSS) vulnerability in the Shift Logbook application of B&R APROL versions up to and including R 4.4-00P3. A network-based attacker can craft a malicious request that causes arbitrary JavaScript to execute in the context of an authenticated user's browser session. Exploitation requires user interaction, typically through a crafted link. The flaw is tracked under CWE-79 (Improper Neutralization of Input During Web Page Generation). APROL is a process control system deployed in industrial environments, making this a relevant concern for operational technology (OT) security teams.

Critical Impact
Successful exploitation allows arbitrary JavaScript execution in the victim's browser, enabling session token theft, UI manipulation, or unauthorized actions against the APROL Shift Logbook interface.

Affected Products

B&R APROL versions <= R 4.4-00P3
Shift Logbook application component
Industrial Automation APROL process control system deployments

Discovery Timeline

2024-08-29 - CVE-2024-5624 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-5624

Vulnerability Analysis

The Shift Logbook application in B&R APROL fails to properly neutralize user-supplied input before reflecting it back into rendered HTML. An attacker who can induce an authenticated user to click a crafted URL causes the malicious payload to be echoed into the response and executed by the browser. Because APROL is used to operate industrial processes, an XSS payload can leverage the victim's authenticated session to interact with the Shift Logbook or adjacent APROL web functionality.

The attack requires network access to the APROL web interface and user interaction. No privileges are required from the attacker, and the impact spans confidentiality, integrity, and availability of the subsequent web session. The EPSS probability is 0.253% at the 16.9th percentile, indicating low observed exploitation activity at this time.

Root Cause

The root cause is missing or inadequate output encoding of request parameters processed by the Shift Logbook application. Input that reaches the HTTP response body is rendered without context-aware escaping, allowing HTML and JavaScript tokens supplied by the attacker to be interpreted by the browser rather than displayed as text.

Attack Vector

An attacker delivers a crafted link, for example via phishing or an embedded link on an attacker-controlled page, that targets a vulnerable Shift Logbook endpoint. When an authenticated APROL user visits the link, the server reflects the payload into the response. The browser then executes the injected script in the origin of the APROL web application, giving the attacker access to cookies, DOM contents, and authenticated request capabilities within that origin.

No verified public proof-of-concept code is available. Refer to the B&R security advisory SA24P2014 for vendor-provided technical detail.

Detection Methods for CVE-2024-5624

Indicators of Compromise

HTTP requests to Shift Logbook endpoints containing script tags, javascript: URIs, event handler attributes such as onerror= or onload=, or encoded variants in query string parameters.
Web server or reverse proxy access logs showing unusually long query strings or URL-encoded HTML metacharacters (%3C, %3E, %22) targeting APROL interfaces.
Browser referrer chains where APROL sessions originate from external or untrusted domains.

Detection Strategies

Deploy web application firewall (WAF) signatures for reflected XSS patterns on the paths serving the Shift Logbook application.
Correlate authenticated APROL sessions with anomalous outbound requests from operator workstations that could indicate session token exfiltration.
Review APROL and reverse proxy logs for repeated 200-response requests carrying suspicious query parameters.

Monitoring Recommendations

Enable verbose HTTP request logging on systems fronting APROL and forward logs to a central analytics platform for retention and search.
Monitor operator endpoints for browser process anomalies, unexpected script execution, or credential-related activity following APROL usage.
Alert on any change to APROL user configurations or logbook entries performed outside of scheduled operator activity.

How to Mitigate CVE-2024-5624

Immediate Actions Required

Identify all APROL installations at or below R 4.4-00P3 and inventory exposure of the Shift Logbook web interface.
Restrict access to the APROL web interface to trusted operator networks using network segmentation and firewall rules.
Brief operators and engineers on the risk of clicking unsolicited links that reference internal APROL hostnames or IP addresses.

Patch Information

B&R has published advisory SA24P2014 covering multiple vulnerabilities in APROL. Apply the vendor-supplied fixed release beyond R 4.4-00P3 as directed in the B&R security advisory SA24P2014. Coordinate patching with plant maintenance windows because APROL supports live process control.

Workarounds

Place the APROL web interface behind a reverse proxy that enforces a strict Content Security Policy (CSP) to limit inline script execution.
Require operators to access APROL only from hardened jump hosts with restricted browsing capability and no general internet access.
Disable or restrict use of the Shift Logbook application until the patch can be applied where operationally feasible.

bash

# Example nginx reverse proxy header hardening in front of APROL
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'none'";
add_header X-Content-Type-Options "nosniff";
add_header X-Frame-Options "DENY";
add_header Referrer-Policy "no-referrer";