Schneider Electric has published a coordinated security advisory addressing a denial‑of‑service (DoS) weakness in its EcoStruxure portfolio that allows an unauthenticated remote actor to exhaust server resources by flooding the OPC UA interface, tracked as CVE‑2024‑10085 and rated as high severity under current scoring; the issue affects EcoStruxure OPC UA Server Expert (versions prior to SV2.01 SP3) and EcoStruxure Modicon Communication Server (all versions), and Schneider’s fix for the OPC UA Server Expert is available in SV2.01 SP3 while mitigations are recommended for other affected components.
Industrial automation stacks increasingly expose OPC UA endpoints to enable telemetry and integration between controllers, HMIs, historians, and enterprise IT. OPC UA is designed to be secure by default, but implementations vary — and a lack of request throttling or resource limits in a server can allow a simple request flood to deny legitimate operations. The vulnerability published as CVE‑2024‑10085 is categorized under CWE‑770 (Allocation of Resources Without Limits or Throttling) and was reported to Schneider Electric by a third‑party researcher. Public trackers and vendor advisories identify the affected eco‑system components and vendor remediation steps.
Why this matters: EcoStruxure components are widely deployed across energy, critical manufacturing, commercial facilities and other critical infrastructure sectors, so availability impairments can produce real operational impact beyond simple IT inconvenience. The advisory explicitly warns that successful exploitation could result in the loss of real‑time process data from the Modicon Controller, a clear operational‑risk outcome for process control and automation teams.
Caveat: when using public trackers, verify the exact build string or SP labels against your installed binary’s version metadata; different regional build tags or packaging can generate confusion during patch validation. If build metadata is not obvious, export the product’s “About” or installation manifest and compare directly to the vendor’s remediation bulletin before applying an update.
Unverifiable claim note: public evidence of in‑the‑wild exploitation was not present in the coordination notices at the time of vendor publication; organizations must nonetheless assume actors will target unpatched, exposed servers because the attack prerequisites are low. Use caution: lack of reported exploitation is not proof that the vulnerability is not being leveraged in targeted intrusions.
Operational security must focus on rapid, measured action: inventory, isolation, configuration hardening, monitoring, and prompt patching once vendor fixes are validated in your environment. Given the low attack complexity and the critical nature of the systems involved, any delay in mitigation increases exposure for operators who connect OT systems to enterprise networks or allow remote vendor access.
(Verified against vendor advisories and independent vulnerability trackers; operators should continue to follow vendor SEVD updates and national CSIRT guidance for any changes to remediation timelines and exploit status.)
Source: CISA Schneider Electric EcoStruxure | CISA
Industrial automation stacks increasingly expose OPC UA endpoints to enable telemetry and integration between controllers, HMIs, historians, and enterprise IT. OPC UA is designed to be secure by default, but implementations vary — and a lack of request throttling or resource limits in a server can allow a simple request flood to deny legitimate operations. The vulnerability published as CVE‑2024‑10085 is categorized under CWE‑770 (Allocation of Resources Without Limits or Throttling) and was reported to Schneider Electric by a third‑party researcher. Public trackers and vendor advisories identify the affected eco‑system components and vendor remediation steps. Why this matters: EcoStruxure components are widely deployed across energy, critical manufacturing, commercial facilities and other critical infrastructure sectors, so availability impairments can produce real operational impact beyond simple IT inconvenience. The advisory explicitly warns that successful exploitation could result in the loss of real‑time process data from the Modicon Controller, a clear operational‑risk outcome for process control and automation teams.
What the advisory says — executive summary
- Vulnerability: Allocation of resources without limits or throttling (CWE‑770), leading to Denial‑of‑Service conditions when a large number of OPC UA requests are sent to the server.
- CVE: CVE‑2024‑10085. Vendor and public trackers list a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and a CVSS v4 base score of 8.2 reported by the vendor.
- Affected products:
- EcoStruxure OPC UA Server Expert: Versions prior to SV2.01 SP3.
- EcoStruxure Modicon Communication Server: All versions.
- Primary impact: Availability — denial of service, loss of real‑time process data.
- Fix availability: OPC UA Server Expert is fixed in SV2.01 SP3; Schneider Electric states a remediation plan is being developed for the Modicon Communication Server. Until that fix is available, vendors and CISA recommend applying configuration and network mitigations.
Technical analysis: how the flaw works
The vulnerability class
The issue belongs to CWE‑770 — Allocation of Resources Without Limits or Throttling. In practical terms, the server accepts and attempts to process more OPC UA requests than it can sustainably handle, without enforcing per‑session or per‑client quotas, request rate limits, or other back‑pressure mechanisms. When overloaded, the server’s worker threads, connection table or memory resources can be exhausted and the server will cease to respond to legitimate traffic.Attack vector and preconditions
- Attack vector: Network (remote, unauthenticated). The server exposes the OPC UA endpoint publicly on reachable networks, and an attacker sends a high volume of crafted or repeated OPC UA requests to consume resources.
- Complexity: Low — a flood or crafted sequence of requests can trigger resource exhaustion if rate‑limiting is absent.
- Privileges: None required — requests need not be authenticated if the server accepts unauthenticated sessions (or if anonymous access or weak authentication is configured).
- Impact: High on availability — services become unresponsive and process data updates are lost, disrupting control and monitoring loops.
Why OPC UA endpoints are attractive targets
OPC UA is often reachable across OT/IT boundaries for integration, and many deployments historically prioritized connectivity over hardened access controls. Without network segmentation, a misconfigured or exposed OPC UA endpoint is a straightforward target for resource‑exhaustion attacks. The weakness here is implementation/operational — the server does not adequately limit or throttle requests.Affected product details and patch status
- EcoStruxure OPC UA Server Expert — Fixed in SV2.01 SP3. Administrators running versions prior to SV2.01 SP3 should schedule immediate testing and deployment of the vendor update.
- EcoStruxure Modicon Communication Server — All versions listed as affected. Schneider Electric has indicated a remediation plan is being developed and will be documented in SEVD‑2025‑287‑01 updates; until a vendor patch ships, operators must apply recommended mitigations and network controls.
Caveat: when using public trackers, verify the exact build string or SP labels against your installed binary’s version metadata; different regional build tags or packaging can generate confusion during patch validation. If build metadata is not obvious, export the product’s “About” or installation manifest and compare directly to the vendor’s remediation bulletin before applying an update.
Mitigations — immediate actions (operational triage)
If you cannot apply the official patch immediately, apply the following layered mitigations recommended by Schneider Electric and echoed by coordination notes:- Apply the vendor patch where available:
- Download and install EcoStruxure OPC UA Server Expert SV2.01 SP3 on affected nodes as soon as operational testing permits.
- Harden OPC UA configuration:
- Set the Security Policy to Basic256‑Sha256 (or stronger) to require secure channel negotiation and prevent weak/no security sessions.
- Ensure Anonymous user token is disabled (unchecked) unless explicitly required and controlled.
- Enforce User authentication and X.509 user token settings to require client credentials and certificate‑based authentication for OPC UA clients. These are product configuration toggles described in the vendor’s user guide.
- Network controls and segmentation:
- Place control and safety system networks behind robust firewalls; deny inbound access to OPC UA endpoints from untrusted networks.
- Isolate OT networks from the corporate/business network; ensure any necessary IT‑OT connections are restricted with controlled gateways and access rules.
- Block or rate‑limit the OPC UA TCP port(s) at perimeter and internal firewalls where possible, allowing only trusted IP ranges and authenticated VPN connections.
- Remote access hygiene:
- If remote access is required, use VPNs with strong mutual authentication and restrict VPN access to known devices; keep VPN appliances updated and monitored.
- Remember that VPNs are not a panacea; patch and harden the endpoints themselves.
- Operational best practices:
- Place controllers in locked cabinets; don’t leave hardware in “Program” mode.
- Scan removable media prior to use on OT systems and sanitize any mobile devices brought into operational environments.
- Conduct immediate inventory and identify exposed OPC UA servers; treat exposed endpoints as high priority for mitigation.
Detection and monitoring guidance
- Baseline normal OPC UA traffic: capture session rates and request patterns for each server during business‑as‑usual windows.
- Create alerts for:
- Sudden spikes in number of OPC UA sessions from a single client IP.
- High rates of Browse/Read/Subscribe/Open requests within short intervals.
- Server thread or process counts increasing beyond normal thresholds.
- Monitor endpoint health: set uptime and responsiveness checks for OPC UA servers and automate failover behaviors where possible.
- Log and retain OPC UA server diagnostics and authentication failures for forensic analysis. Correlate unusual OPC UA traffic with firewall logs and VPN sessions.
Risk evaluation — who should care and why
- Operators in Energy, Critical Manufacturing, Commercial Facilities, and Water sectors should prioritize remediation: availability loss can translate into safety risk, production downtime, or cascading control failures.
- System integrators and managed service providers who host or remotely manage EcoStruxure environments must inventory customer exposures and schedule patch windows.
- IT teams responsible for OT connectivity must treat OPC UA endpoints as critical assets and ensure they are not reachable from untrusted networks or the internet.
Unverifiable claim note: public evidence of in‑the‑wild exploitation was not present in the coordination notices at the time of vendor publication; organizations must nonetheless assume actors will target unpatched, exposed servers because the attack prerequisites are low. Use caution: lack of reported exploitation is not proof that the vulnerability is not being leveraged in targeted intrusions.
Practical remediation checklist (step‑by‑step)
- Inventory:
- Identify all instances of EcoStruxure OPC UA Server Expert and Modicon Communication Server in the environment.
- Record installed build strings and patch levels from product “About” pages.
- Isolate:
- Immediately block external access to OPC UA endpoints at the network perimeter.
- Restrict internal access to only trusted engineering/SCADA subnets.
- Configure:
- Enforce Basic256‑Sha256 or stronger Security Policy.
- Disable anonymous authentication; require user and X.509 authentication for clients.
- Apply quota/rate controls on gateway/proxy devices where possible.
- Patch:
- Test SV2.01 SP3 of OPC UA Server Expert in a pre‑production environment.
- Roll out patches following change‑control with scheduled rollbacks and backups.
- Monitor:
- Implement detection rules for anomalous session/request spikes and trigger incident response playbooks.
- Plan:
- For Modicon Communication Server (until vendor patch), maintain tight segmentation and consider temporary take‑down of publicly reachable endpoints where feasible.
- Subscribe to vendor security notifications for update bulletins and SEVD revisions.
Strengths and limitations of the vendor response
Notable strengths
- Schneider Electric published a coordinated advisory and provided a fix for OPC UA Server Expert (SV2.01 SP3) promptly for that component, reducing exposure for users who upgrade. Public trackers and national CSIRTs have republished the coordinated message, helping visibility.
- Vendor guidance includes actionable configuration mitigations (security policy tightening, disabling anonymous tokens) and recommends standard OT best practices (segmentation, physical controls, minimal remote exposure) which are aligned with industry guidance for ICS security.
Potential gaps and risks
- Modicon Communication Server remains listed as affected across all versions with a remediation plan pending — this creates a multi‑month operational exposure window for organizations that rely on that component. Reliance on mitigations and network controls increases operational complexity and management overhead.
- The advisory’s emphasis on configuration and network mitigations is necessary, but sometimes insufficient in environments where architectural constraints make segmentation difficult (legacy integrations, contractor VPN access). Operators must plan for more substantial compensating controls or temporary service restrictions.
- Practical detection of resource‑exhaustion attacks can be challenging in high‑traffic OT environments where legitimate telemetry bursts can mimic attack patterns; careful baseline and tuning are required to avoid false positives.
Recommended governance and long‑term actions
- Treat ICS and OT software vulnerabilities with the same urgency as critical IT patches: track them in a vulnerability management system, score them against operational impact, and schedule patch windows with operational owners—not solely IT.
- Implement defense‑in‑depth for OT:
- Network segmentation and strict firewall policies.
- Application gateways / protocol proxies that can implement request throttling and deep protocol inspection for OPC UA.
- Multi‑layer monitoring with OT‑aware detection rules.
- Harden engineering workstations and restrict their network exposure; apply endpoint hardening, application allow‑listing, and regular malware scans.
- Conduct table‑top exercises that simulate DoS on control servers to validate incident response — including safe rollback plans and manual operational workarounds if telemetry is lost.
Timeline and disclosure context
- The vendor assigned CVE‑2024‑10085 and coordinated the release of a security bulletin; third‑party trackers and national CERT/CSIRT posts followed, mirroring the vendor's affected product list and guidance. Commercial vulnerability feeds list the CVE and scoring. This coordinated disclosure model is the modern standard for ICS vendors and seeks to balance operator preparedness with responsible publication.
- As stated in the advisory material reproduced in operational reporting, there were no known public exploitation reports to CISA at the time of advisory publication. That status should be treated as transient; monitor vendor, CISA and national CSIRT updates for any change.
Conclusion — operational takeaway
CVE‑2024‑10085 is a practical, high‑impact availability vulnerability because it can be exploited remotely with low complexity against exposed OPC UA endpoints. The immediate priority for defenders is to inventory affected EcoStruxure components, apply SV2.01 SP3 to EcoStruxure OPC UA Server Expert where possible, and implement the vendor‑recommended hardening and network mitigations for all affected devices — especially Modicon Communication Server instances that remain pending a formal patch.Operational security must focus on rapid, measured action: inventory, isolation, configuration hardening, monitoring, and prompt patching once vendor fixes are validated in your environment. Given the low attack complexity and the critical nature of the systems involved, any delay in mitigation increases exposure for operators who connect OT systems to enterprise networks or allow remote vendor access.
(Verified against vendor advisories and independent vulnerability trackers; operators should continue to follow vendor SEVD updates and national CSIRT guidance for any changes to remediation timelines and exploit status.)
Source: CISA Schneider Electric EcoStruxure | CISA