Threat Hunt Plan: ABB Ability zenon IIoT Services — End-of-Life MongoDB Component Exposure and Memory-Disclosure Exploitation

Version 1.0 — 3 August 2026

Hunt Objective and Scope

This hunt seeks evidence of reconnaissance, exploitation, denial of service, and post-exploitation activity against the end-of-life MongoDB 4.2 instance bundled with the IIoT Services component of ABB Ability zenon, as disclosed in ABB cyber security advisory 9AKK108472A9037 dated 30 July 2026. The advisory covers thirteen publicly disclosed MongoDB vulnerabilities that will never be patched in the 4.2 branch. The dominant hunt driver is CVE-2025-14847, publicly known as MongoBleed, which permits an unauthenticated client to read uninitialized heap memory from the database process because the zlib decompression path returns the allocated output buffer size instead of the actual decompressed length. CISA added CVE-2025-14847 to the Known Exploited Vulnerabilities catalog on 29 December 2025 and public proof-of-concept code exists, so the hunt assumes opportunistic scanning and exploitation are already occurring against reachable listeners.

Environment in scope: every host running ABB Ability zenon with IIoT Services installed, including the MongoDB-based Persistence Service; every engineering workstation, HMI, SCADA server, and historian that communicates with those hosts; the Level 3 and Level 3.5 network segments where IIoT Services typically bridge process and enterprise networks; and any internet-facing or vendor-facing network path that terminates on a zenon or IIoT Services host. Hosts running zenon without IIoT Services do not bundle MongoDB and are out of scope, but their exclusion must be evidenced by inventory rather than assumed.

Time window: retrospective 180 days from hunt start, with a mandatory deep-dive on the period from 29 December 2025 forward (the KEV listing date, after which mass scanning for CVE-2025-14847 became likely). Where telemetry retention is shorter than 180 days, hunt the full available window and record the retention limit as a coverage gap in the final report. Long-running database daemons emit process-start telemetry only at start, so any CrowdStrike process-attribution query must be run across at least a 90-day window and preferably one year, otherwise a mongod service that has been running uninterrupted since before the window began will return zero matches and read as a false negative.

Out of scope: exploitation of MongoDB deployments unrelated to zenon; the local privilege escalation in MongoDB Compass for Windows (CVE-2021-20334) except where Compass is confirmed installed on a zenon engineering workstation; and remediation execution, which is a separate change-managed activity governed by the advisory mitigation guidance.

Hypotheses and Hunt Procedures

Hypothesis 1: An unauthenticated external or internal actor has probed or exploited the MongoBleed memory-disclosure flaw against the MongoDB listener bundled with zenon IIoT Services, observable as inbound connections to the MongoDB service ports from unsanctioned sources and as malformed or anomalous zlib-compressed wire-protocol messages in network capture.

MITRE ATT&CK: Reconnaissance | T1595.002 — Active Scanning: Vulnerability Scanning | opportunistic scanners enumerate exposed MongoDB listeners and fingerprint version banners before exploitation. Initial Access | T1190 — Exploit Public-Facing Application | the MongoDB wire protocol listener is the exposed application. Credential Access | T1212 — Exploitation for Credential Access | the disclosed heap memory frequently contains credentials, session tokens, and API keys. ICS | T0866 — Exploitation of Remote Services | the affected service sits inside the industrial environment.

Collection Queries

CrowdStrike Falcon LogScale (CQL) — enumerate every host exposing a MongoDB listener, which establishes the true hunt population independent of the software inventory:

CrowdStrike Falcon LogScale (CQL) — all inbound accepts on the MongoDB service ports, to establish the sanctioned client baseline:

CrowdStrike Falcon LogScale (CQL) — inbound accepts sourced from outside RFC 1918 space, which for an OT-resident database is an immediate finding rather than a candidate:

CrowdStrike Falcon LogScale (CQL) — process attribution for the listening service. The connection event does not carry ImageFileName, so ProcessRollup2 is the main query and the filtered connection set is the subquery (reverse-direction join). Run this across at least 90 days:

BPF packet capture — targeted capture of MongoDB wire-protocol traffic at the IIoT Services host, rolling hourly with a size guard. The strftime format in the output filename is mandatory or each rotation overwrites the previous file:

Datadog Log Search — inbound connection events on the MongoDB ports from Windows hosts running zenon IIoT Services:

Datadog Log Search — MongoDB server log ingestion, where the mongod log is forwarded as a custom source:

Datadog Live Process Monitoring (Infrastructure > Processes — not a log source, separate interface):

Data source gap note: VPC and OT-segment flow logs are frequently not forwarded to Datadog in industrial deployments, and Live Process Monitoring is often not licensed on Purdue Level 2 and Level 3 hosts because of agent-footprint restrictions. Where either gap applies, substitute the source:windows Event ID 5156 and 4688 log searches above and record the substitution in the coverage section of the hunt report.

Windows Event IDs to collect:

• 5156 — Windows Filtering Platform permitted a connection (inbound connections to the MongoDB listener)
• 5157 — Windows Filtering Platform blocked a connection (blocked probe attempts, equally probative of scanning)
• 4688 — A new process has been created (mongod.exe and MongoDB tool invocations)
• 7036 — Service Control Manager: service entered the running or stopped state (MongoDB service state transitions)
• 4624 and 4625 — successful and failed logon on the IIoT Services host

OT Data Collection: Claroty xDome — Devices > All Devices > Advanced Filters, filter Device Type = "SCADA Server" and Device Type = "Industrial Workstation" to build the zenon host population, then use the Protocols & Ports chip to isolate devices exposing port 27017. Then Network > Communication > Communication Analysis: leave Side A empty, set Communication bucket Port = 27017 (add rows with + OR for 27018 and 27019), set Side B to the device set identified above, and set Time Frame to Past Quarter. Export the resulting flow set. Do not encode the time window as a bucket row — Time Frame is a separate dropdown below the buckets.

OT Data Collection: Claroty CTD — the on-prem platform is a different product from xDome with different PCAP retention; use the CTD console's own flow view and pull the packet capture for any flagged MongoDB conversation directly from the CTD sensor, which retains substantially more raw traffic than xDome.

OT Data Collection: Dragos Platform — in Assets, scope to the zenon and IIoT Services host population by vendor and Purdue level and carry it forward as the hunt population. In the Communications Hub, filter destination port 27017 across a 30-day window with source zone set to Level 3.5 or Level 4 and destination zone Level 2 or Level 3, which surfaces every cross-Purdue MongoDB session in one query, then pivot each session to its asset record and event PCAP. Query the Server Stats / PCR Query Focused Dataset for any peer of an IIoT Services host trending toward a producer-consumer ratio near minus 0.99, which is the exfiltration signature. Export the event PCAP or use Export PCAP for window from SiteStore for offline analysis.

OT Data Collection: Nozomi Guardian and Vantage — run the following N2QL queries and export the results:

OT Data Collection: Armis Centrix — run the following ASQ in the console search bar. Set the time window in the UI time-picker (Past Month minimum); do not embed timeFrame in the query body. Where the tenant has boundary literals provisioned, add device:(boundary:"<your tenant literal>") inside the endpoint predicate to scope to the OT zone:

OT Data Collection: Tenable OT Security — in Inventory > All Assets, filter to Windows-based OT assets and export the asset list; in Risks > Findings, filter by Plugin Name for MongoDB plugins and by affected asset to enumerate hosts where the plugin pipeline has matched a MongoDB CVE. Use the GraphQL endpoint for any repeatable sweep; note that the origins field is deprecated in favour of networkAreas as of v4.7.44, so update existing hunt scripts accordingly.

OT Data Collection: Forescout eyeInspect — use the Command Center Asset Inventory view filtered by Purdue level and vendor to identify zenon hosts, and the Alerts view filtered by protocol and destination port for MongoDB flows. eyeInspect has no analyst-facing query language, so forward CEF or syslog to the SIEM and perform the free-text correlation there; the Forescout OT Network Security Monitoring App for Splunk is the canonical path.

SNMP polling — poll the switch port facing each IIoT Services host to detect the traffic volume signature of repeated memory-disclosure requests, which produce a high count of small requests with disproportionately large responses:

Poll at 60-second intervals across the hunt window and diff successive values; a sustained outbound-to-inbound octet ratio far above the historical baseline on the IIoT host port is the volumetric signature of bulk heap-memory harvesting. Prefer SNMPv3 authPriv throughout and provision credentials via snmp.conf rather than inline flags, since inline passphrases are visible in the process table. Where a device offers only SNMPv1 or v2c community-string access, record that as a finding in its own right. Collect trap-receiver logs for the window and flag coldStart (1.3.6.1.6.3.1.1.5.1) and warmStart (1.3.6.1.6.3.1.1.5.2) traps from the IIoT host range, which corroborate the denial-of-service hypothesis, and authenticationFailure (1.3.6.1.6.3.1.1.5.5) traps indicating unauthorized access attempts.

YARA file-system scan — scan the zenon installation tree and the MongoDB data and binary directories for end-of-life component artifacts and for staged exploitation tooling:

Analysis Queries

CrowdStrike Falcon LogScale (CQL) — rate analysis on inbound MongoDB accepts, bucketed by hour, to separate a sanctioned polling client from a scanner or a repeated memory-harvesting loop. The formatTime approach is used instead of bucket() because bucket()'s limit parameter caps series at 500 and would silently truncate a fleet-wide hunt:

Wireshark display filters — isolate MongoDB wire-protocol traffic and the specific opcode used by MongoBleed. Opcode 2012 (0x000007DC) is OP_COMPRESSED; compressor identifier 2 is zlib:

The third and fourth filters are the highest-value analytical step in this hunt. A client that sends OP_COMPRESSED messages whose declared uncompressed size does not match the actual decompressed payload is exercising the vulnerable code path, and a response frame substantially larger than the request that produced it is the observable signature of leaked heap memory returning to the attacker.

Datadog Log Analytics — inbound MongoDB connection distribution by source:

Datadog Log Analytics — rarity analysis to surface the source addresses that appear least often, which is where a one-off exploitation attempt hides:

Datadog CloudTrail integration — where IIoT Services or its MongoDB instance runs on cloud infrastructure, examine security-group and network-ACL modifications that could have exposed the listener:

Datadog Audit Trail — confirm no monitoring or log-forwarding configuration was altered around the suspect window, which would indicate an attempt to blind the defender:

Datadog Monitor definition:

Windows Event Log PowerShell analysis — connection hunting and source-address frequency ranking:

Sorting ascending rather than descending is deliberate: the sanctioned Persistence Service client will dominate the top of a descending sort, while a single exploitation attempt appears exactly once and would be buried.

OT network and protocol analysis — for each flagged MongoDB conversation, export the PCAP from Dragos or Claroty CTD and analyse offline. Correlate the timestamp of every flagged conversation against the historian for gaps in process-value recording and against the SCADA alarm log for communication-failure alarms on the IIoT Services host, since a successful denial of service against mongod manifests operationally as a historization gap before it manifests as a security alert. Baseline the flagged source against the platform's learned communication model — in Nozomi this is the link baseline, in Claroty the Communication Analysis flow history, in Dragos the Communications Hub baseline status attribute — and treat any source that has no prior communication history with the IIoT host as a priority finding regardless of volume.

YARA memory scan — scan the running mongod process and any suspicious child process for exploitation tooling resident in memory. Classic YARA 4.5.x is required for process-memory scanning; YARA-X (binary yr) has no PID scanning capability:

Where hosts cannot be reached interactively, CrowdStrike Falcon Real Time Response can execute the YARA binary and rule file on remote endpoints via the put and run commands, and a Custom IOA can be authored to alert on the process-creation pattern once the hunt has validated it.

Hypothesis 2: An actor has triggered one or more of the denial-of-service vulnerabilities in the bundled MongoDB 4.2 component, observable as repeated mongod process termination and restart cycles, MongoDB service state transitions outside the change window, and corresponding gaps in zenon historization and reporting.

MITRE ATT&CK: Impact | T1499.004 — Endpoint Denial of Service: Application or System Exploitation | six of the thirteen CVEs crash the database process through crafted queries, aggregation pipelines, role names, or oplog entries. ICS | T0814 — Denial of Service | the industrial consequence of the crashed service. ICS | T0826 — Loss of Availability | historization and integration functions become unavailable. ICS | T0815 — Denial of View | operators lose the trend and reporting view built on the Persistence Service data.

Collection Queries

CrowdStrike Falcon LogScale (CQL) — mongod process start events, grouped by parent, which reveals both the restart frequency and whether restarts are service-manager driven or something else:

CrowdStrike Falcon LogScale (CQL) — process lifetime derivation. EndOfProcess does not carry ImageFileName, so the image name must come from ProcessRollup2 and the end time is joined in: