Rockwell ControlLogix 5580 denial-of-service flaw
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NULL pointer dereference in ControlLogix 5580 v35.013 causes nonrecoverable controller faults via remote message forwarding.
Rockwell Automation disclosed a denial-of-service vulnerability in ControlLogix 5580 version 35.013, identified as CVE-2025-9166. The flaw stems from a NULL pointer dereference (CWE-476) in message handling that causes the controller to repeatedly attempt to forward messages, resulting in a major nonrecoverable fault. The vulnerability is remotely exploitable with low attack complexity and requires no authentication or user interaction, making it a practical threat to exposed deployments. CVSS v3 base score is 7.5; CVSS v4 score is 8.2.
The vulnerability affects critical manufacturing infrastructure worldwide. No active exploitation in the wild has been reported to CISA as of the advisory date. Rockwell recommends immediate upgrade to version 35.014 or later. Organizations unable to patch should apply defense-in-depth controls: isolate control system networks from the internet and business networks, place systems behind firewalls, and use secure remote access methods such as VPNs when remote management is required.
Mentioned in this report
Detection guidance
Scripting or Network Tool Connecting to EtherNet/IP Port
Non-engineering processes such as scripting runtimes or netcat opening connections to EtherNet/IP ports 44818 or 2222, consistent with crafted CIP message delivery to a PLC. 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: Scripting or Network Tool Connecting to EtherNet/IP Port
id: 602cbf74-bf27-58af-b9cb-4f8122847fe3
status: experimental
description: Detects scripting runtimes or generic network tools on a Windows host
opening outbound connections to EtherNet/IP ports (44818 or 2222). Legitimate access
to Logix controllers normally comes from Rockwell engineering software such as Studio
5000 or RSLinx. Crafted CIP messages sent by script or tool could be used to trigger
a denial-of-service fault such as CVE-2025-9166 in ControlLogix 5580.
references:
- https://www.cisa.gov/news-events/ics-advisories/icsa-25-252-07
tags:
- attack.impact
- attack.t1499.004
logsource:
category: network_connection
product: windows
detection:
selection:
Initiated: 'true'
DestinationPort:
- 44818
- 2222
Image|endswith:
- \python.exe
- \pythonw.exe
- \powershell.exe
- \pwsh.exe
- \cmd.exe
- \wscript.exe
- \cscript.exe
- \nc.exe
- \ncat.exe
- \nmap.exe
condition: selection
falsepositives:
- OT engineers running Python-based CIP or pycomm3 tooling for legitimate inventory
or data collection
- Authorised ICS asset discovery scans run from a scripting host
level: medium
author: Vorant
Inbound EtherNet/IP Traffic to Controllers from Non-Private Sources
Allowed traffic to EtherNet/IP port 44818 originating from public address space, indicating exposed controllers reachable for remote DoS exploitation. 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: Inbound EtherNet/IP Traffic to Controllers from Non-Private Sources
id: 12d96e69-cc62-5ce7-ab0c-cec847959ee1
status: experimental
description: Detects firewall-allowed connections to the EtherNet/IP port 44818 from
non-RFC1918 source addresses. Internet-reachable Logix controllers such as ControlLogix
5580 are exposed to unauthenticated remote denial-of-service flaws like CVE-2025-9166.
Tune the filter to include the organisation's own public or VPN ranges.
references:
- https://www.cisa.gov/news-events/ics-advisories/icsa-25-252-07
tags:
- attack.impact
- attack.t1499.004
logsource:
category: firewall
detection:
selection:
dst_port: 44818
action: allowed
filter_internal:
src_ip|cidr:
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
- 127.0.0.0/8
condition: selection and not filter_internal
falsepositives:
- Authorised remote vendor or integrator access arriving from a known public IP range
- Site-to-site links that present public NAT addresses to the OT firewall
level: medium
author: Vorant
Behavioural rules are generated from public reporting — validate in your environment before deploying.
Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-252-07
What this brief leaves out
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