Libiec61850 flaws enable IEC 61850 DoS attacks
Eight unpatched CVEs in MZ Automation's libiec61850 let attackers crash GOOSE/MMS substation automation processes with a single malformed packet.
Sourcecisa.gov — open the original
What to check
- Applies to
- The 8 CVEs named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
CISA published an ICS advisory covering eight denial-of-service vulnerabilities in MZ Automation GmbH's libiec61850 library, versions prior to 1.6.2. The flaws span multiple protocol-handling components used in IEC 61850 substation automation: the GOOSE subscriber and payload parsers, the MMS BER decoder, the MMS server connection handler, the ACSE layer, and the ISO Presentation layer. All eight are out-of-bounds read issues (CWE-125) triggerable by a single crafted, often unauthenticated, packet—either a Layer-2 GOOSE multicast frame or a TCP/102 MMS/ISO session—causing the affected process to crash.
Because GOOSE messages are unauthenticated by design and MMS/ISO sessions run over a well-known port, an attacker with network access to a substation's process bus or station bus could remotely terminate protection or automation processes, disrupting monitoring and control functions in energy-sector environments. Libiec61850 is deployed worldwide in industrial control and substation automation products, so the exposure is broad but requires network reachability to the affected device—CISA's standard guidance to isolate ICS networks and avoid internet exposure substantially reduces risk.
MZ Automation has released version 1.6.2 to remediate all eight issues. CISA states no public exploitation of these vulnerabilities has been reported. The vulnerabilities were responsibly disclosed by a researcher at the Central Power Research Institute.
Mentioned in this report
Detection guidance
Substation Automation Service Unexpected Termination After Network Session
A behavioural hunt for the technique in general, not a signature for the CVEs this report names.
Detects a Windows Service Control Manager event indicating a service terminated unexpectedly, which combined with prior inbound TCP/102 (MMS/ISO) or GOOSE traffic to the host can indicate a remote crash-inducing DoS against IEC 61850 protection/automation processes. 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: Substation Automation Service Unexpected Termination After Network Session
description: Detects Service Control Manager events (EventID 7031/7034) reporting
that a service terminated unexpectedly. When observed on hosts running IEC 61850
substation automation/protection software shortly after inbound traffic on TCP/102
(MMS/ISO) or GOOSE multicast, this pattern is consistent with remote exploitation
of libiec61850 out-of-bounds read DoS flaws crashing the protocol-handling process.
Investigate correlated network sessions rather than relying on this event alone.
tags:
- attack.impact
- attack.t1499.004
logsource:
product: windows
service: system
detection:
selection:
EventID:
- 7031
- 7034
condition: selection
falsepositives:
- Routine service crashes unrelated to network exploitation (bugs, resource exhaustion,
planned restarts)
- Service updates or patch deployments causing intentional restarts
level: low
id: b441bf2a-e3bd-5308-8a5e-0f230e90855f
status: experimental
author: Vorant
Inbound TCP Session to MMS Port 102 Followed by Immediate Reset
A behavioural hunt for the technique in general, not a signature for the CVEs this report names.
Detects short-lived inbound TCP sessions to port 102 (ISO/MMS) that terminate abnormally quickly, a pattern consistent with a single crafted packet crashing the MMS server/ACSE/ISO presentation layer parser in libiec61850 before a normal session could be established. 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 TCP Session to MMS Port 102 Followed by Immediate Reset
description: Flags inbound network connections to TCP/102 (ISO/MMS, used by IEC 61850
station bus communications) that are unusually short-lived or immediately reset.
Because libiec61850 out-of-bounds read flaws can be triggered by a single crafted
MMS/ISO/ACSE packet causing the server to crash, a burst of very short sessions
to a substation automation host on this port merits investigation. Session-duration/count
thresholds should be tuned and evaluated over a rolling window by the SIEM correlation
layer, not encoded in this single-event rule.
tags:
- attack.impact
- attack.t1499.004
logsource:
category: network_connection
product: windows
detection:
selection:
DestinationPort: 102
Initiated: true
condition: selection
falsepositives:
- Normal, brief MMS client polling or health-check connections from legitimate SCADA/HMI
systems
- Network scanners or asset-discovery tools probing port 102
level: low
id: e8cca14e-e1a4-5eaa-a794-4ade6538fa5f
status: experimental
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-26-211-10
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