CVE-2024-8933: Message Integrity DOS Vulnerability

CVE-2024-8933 Overview

CVE-2024-8933 is a high-severity vulnerability tracked under CWE-924: Improper Enforcement of Message Integrity During Transmission in a Communication Channel. The flaw allows an attacker positioned on the logical network to retrieve a password hash exchanged between an engineering workstation and an affected controller. Successful exploitation can lead to denial of service and loss of confidentiality and integrity of the controllers. The attack requires the adversary to be present inside the logical network while a valid user uploads or downloads a project file to the controller.

Critical Impact
Network-adjacent attackers can capture password hashes during project file transfers, enabling controller compromise and operational disruption in industrial environments.

Affected Products

Schneider Electric industrial controllers identified in the vendor advisory SEVD-2024-317-02
Engineering workstation software used to upload or download project files to affected controllers
Industrial control system (ICS) environments using the impacted communication channel without integrity enforcement

Discovery Timeline

2024-11-13 - CVE-2024-8933 published to the National Vulnerability Database
2026-04-15 - Last updated in NVD database

Technical Details for CVE-2024-8933

Vulnerability Analysis

The vulnerability resides in the communication channel between engineering software and the affected controller. The protocol does not enforce message integrity during project file upload and download operations. An attacker with network adjacency can intercept the authentication exchange and extract a transmitted password hash.

The captured hash can be reused to authenticate to the controller, modify logic, or trigger a denial of service. The CWE-924 classification reflects the absence of cryptographic integrity protections that would otherwise prevent tampering or replay of transmitted authentication material. The EPSS probability is 0.093%, indicating low observed exploitation activity at this time.

Root Cause

The root cause is the lack of integrity enforcement on messages exchanged during project transfer operations. The protocol design transmits authentication artifacts without binding them to a session-specific integrity check. This allows a network-positioned adversary to observe and extract the password hash from in-flight traffic.

Attack Vector

Exploitation is network-based but requires specific conditions. The attacker must first gain a foothold on the logical network segment carrying engineering traffic. The attacker must then wait for a legitimate user to perform a project upload or download against the controller. During that window, the adversary captures the exchange and recovers the password hash.

No verified proof-of-concept code is publicly available. The vulnerability is described in the Schneider Electric Security Advisory SEVD-2024-317-02.

Detection Methods for CVE-2024-8933

Indicators of Compromise

Unexpected project upload or download sessions originating from non-engineering workstations
Unauthorized authentication attempts against controllers using captured credentials
Anomalous traffic on engineering protocol ports during off-hours or maintenance windows
Repeated session establishment from a single host targeting multiple controllers

Detection Strategies

Deploy industrial network monitoring to baseline normal engineering workstation behavior and alert on deviations
Inspect ICS protocol traffic for unauthorized project file transfer operations
Correlate controller authentication events with approved change management windows
Monitor for ARP spoofing, rogue hosts, or man-in-the-middle indicators on engineering VLANs

Monitoring Recommendations

Log every project upload and download event on the controller and forward to a SIEM for review
Track session source IP addresses and flag sessions from unexpected hosts
Alert on repeated authentication failures that may indicate hash replay attempts
Review network segmentation enforcement logs between engineering, operations, and corporate networks

How to Mitigate CVE-2024-8933

Immediate Actions Required

Apply the remediation guidance published in the Schneider Electric Security Advisory SEVD-2024-317-02
Restrict project upload and download operations to trusted engineering workstations on isolated network segments
Rotate controller passwords on devices that may have had hashes exposed during transfers
Enable network access controls that prevent unauthorized hosts from reaching controller management interfaces

Patch Information

Refer to the Schneider Electric advisory SEVD-2024-317-02 for affected product versions, fixed firmware releases, and detailed remediation steps. Apply vendor-supplied firmware updates during a planned maintenance window and validate controller functionality after the upgrade.

Workarounds

Segment engineering networks from corporate and operational networks using firewalls and access control lists
Use a VPN or encrypted tunnel for all engineering workstation to controller communication
Limit physical and logical access to the engineering network to authorized personnel only
Schedule project file transfers during controlled windows and monitor those sessions in real time

bash

# Example: restrict controller management traffic to a defined engineering host
# Replace placeholders with values from your environment
iptables -A FORWARD -s <engineering_workstation_ip> -d <controller_ip> -p tcp --dport <engineering_port> -j ACCEPT
iptables -A FORWARD -d <controller_ip> -p tcp --dport <engineering_port> -j DROP