Agentic AI used for post-exploitation in breach of the Dutch Institute for Vulnerability Disclosure (DIVD)

Agentic AI used for post-exploitation in breach of the Dutch (TL-2026-2793) is a high-severity tracked intrusion set, first published 2026-09-29. It has no confirmed attribution, affects Dutch Institute for Vulnerability Disclosure (DIVD) Undisclosed system, maps to 5 MITRE ATT&CK techniques (T1059, T1110.003, T1190), and is covered by 9 detection rules and 7 indicators of compromise.

Key facts for TL-2026-2793

Threat ID
TL-2026-2793
Severity
HIGH
Status
ACTIVE
Category
THREAT_INTEL
First published
2026-09-29
Last reviewed
2026-09-29
Attribution confidence
LOW
Motivation
UNKNOWN
Target sectors
cybersecurity, nonprofit, research
Target regions
netherlands, Europe
Detection rules
9
Indicators of compromise
7

Malware and tooling in Agentic AI used for post-exploitation in breach of the Dutch

Malware and tooling: Autonomous agentic AI post-exploitation agent (unidentified model/framework)

The Dutch Institute for Vulnerability Disclosure (DIVD), a volunteer-run security nonprofit, disclosed a breach in which an unidentified attacker exploited a technical vulnerability in an undisclosed system and then used an autonomous agentic AI for post-exploitation, including password spraying and an adversary-in-the-middle operation. DIVD called the intrusion 'loud and very, very messy'. The scope of compromised data is not yet established.

How Agentic AI used for post-exploitation in breach of the Dutch works

On 2026-09-24 (23:34 CEST) DIVD's CSIRT published 'It was a matter of when, not if…', disclosing that it had noticed suspicious activity in its infrastructure, concluded a breach had occurred, blocked access to its infrastructure, and engaged an external incident response team for forensics. DIVD said this was the first breach it had suffered in nearly seven years of operation, and that it was treating the incident as a worst-case scenario, assuming compromise until proven otherwise.

Initial access: according to DIVD (as reported by BleepingComputer, DataBreaches.net and Beinsure), the actor exploited a technical vulnerability in an undisclosed system. DIVD stated the vulnerability is not Citrix NetScaler. No CVE, product name or vendor has been published; DIVD is withholding details to avoid influencing the investigation and to protect other potentially affected victims, which it plans to notify.

Post-exploitation: DIVD stated 'This is an attack we have not seen before. Not because it's our first, but because the modus operandi indicates that this is an agentic AI-powered attack.' Evidence indicates the agent chose its next action after each previous step rather than following a pre-scripted sequence. It operated quickly but with sloppy logic, performed password spraying while simultaneously running an adversary-in-the-middle operation (thereby interfering with its own AiTM activity), and left comments explaining many of its actions in the code it produced. The intrusion was unusually noisy and left substantial forensic evidence. DIVD suggested the agent appeared poorly trained or configured for offensive security work.

Response and status: DIVD reported the incident to the Autoriteit Persoonsgegevens (Dutch data protection authority) and the NCSC, and consulted/informed the police. Directly affected parties were notified. Whether data was accessed, stolen or altered is unconfirmed. The actor's identity, the vulnerable product and the exact affected systems are undisclosed. No IOCs (IPs, domains, hashes) were published. DIVD's initial notice scheduled an update for 2026-09-28; reporting on 2026-09-29 cites a further detailed update promised for 2026-10-01. Severity is an analyst estimate pending confirmation of impact.

MITRE ATT&CK techniques used in TL-2026-2793

Execution

T1059 Command and Scripting Interpreter

Credential Access

T1110.003 Password Spraying; T1557 Adversary-in-the-Middle

Initial Access

T1190 Exploit Public-Facing Application

Resource Development

T1588.007 Obtain Capabilities: Artificial Intelligence

Affected products and versions in Agentic AI used for post-exploitation in breach of the Dutch

  • Dutch Institute for Vulnerability Disclosure (DIVD) — Undisclosed system with an undisclosed technical vulnerability (DIVD states not Citrix NetScaler)

Remediation for Agentic AI used for post-exploitation in breach of the Dutch

Patches

  • No CVE or vendor patch identified; DIVD states the flaw is not Citrix NetScaler. Monitor the DIVD CSIRT update promised for 2026-10-01

Immediate actions

  • Hunt authentication logs for low-and-slow and high-volume password spraying against VPN, SSO/IdP, OWA and admin portals, and enforce lockout/throttling and MFA
  • Review internal network segments for rogue ARP/DHCP/LLMNR/NBT-NS/WPAD responders and other adversary-in-the-middle activity
  • Look for scripts or tool output containing verbose, explanatory natural-language comments dropped on hosts, which DIVD reported as an artifact of the agent
  • Rotate credentials for accounts exposed to the affected infrastructure and apply patches for internet-facing systems as vendor fixes emerge

Workarounds

  • Isolate or restrict access to affected internet-facing systems until the vulnerable product is identified
  • Block or rate-limit repeated authentication failures per source and per account

Longer-term hardening

  • Reduce internet-facing attack surface and keep an accurate inventory of exposed services
  • Deploy behavioral EDR/NDR that detects rapid, sequential, adaptive post-exploitation rather than fixed tooling signatures
  • Enforce phishing-resistant MFA and conditional access to blunt credential spraying and AiTM credential capture
  • Prepare an open, transparent incident-communication process modeled on DIVD's disclosure

Timeline of Agentic AI used for post-exploitation in breach of the Dutch

  • DIVD established as a Dutch volunteer-run coordinated vulnerability disclosure nonprofit; DIVD says the 2026 incident is its first breach in nearly seven years of operation
  • DIVD CSIRT publishes 'It was a matter of when, not if…' (23:34 CEST), stating the modus operandi indicates an agentic AI-powered attack and that the incident was reported to the Autoriteit Persoonsgegevens, NCSC and police
  • DIVD notices suspicious activity in its infrastructure, concludes a breach occurred, blocks access to infrastructure and engages an external incident response team
  • DataBreaches.net reports DIVD is investigating an agentic AI-powered attack; DIVD treating it as a worst-case scenario
  • Scheduled DIVD update date; DIVD provides an incident update describing the agent's behavior (next-step decisions, password spraying interfering with its own AiTM, explanatory code comments) and that the flaw is not Citrix NetScaler
  • BleepingComputer publishes details of the automated AI agent used to breach DIVD; scope of data compromise still undetermined
  • DIVD promises a detailed update, including disclosures about other potential victims of the same vulnerability

Sources cited for Agentic AI used for post-exploitation in breach of the Dutch

More in threat intel

Detection coverage for TL-2026-2793

As of 2026-09-29, Threadlinqs Intelligence publishes 9 detection rule(s) for TL-2026-2793 across Splunk SPL, Microsoft KQL and Sigma, covering 7 indicator(s) of compromise. The whole corpus is readable without an account; a free account unlocks full detection query text in Splunk SPL, Microsoft KQL and Sigma; paid tiers add raw indicator values, correlation and the MCP server. Threadlinqs MCP server · View plans.

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