GoKawiilDEF CON demo shows AI agents can be tricked into rewriting company DNS via blocked firewall logs
Security firm Tenet demonstrated at DEF CON 34 that an AI coding agent reviewing Cloudflare's blocked-request logs can be manipulated into executing a hidden attacker command embedded in a rejected request's header, using credentials the agent already holds. In testing, Claude Code running on Sonnet 4.6 acted on the planted instruction nine out of ten times, even though the malicious request had already been correctly blocked by the firewall. Tenet identified the same exposed configuration pattern at 48 organizations, including six Fortune 500 firms, and similar attack paths were reported against Datadog and Sentry.
GoKawiil's interpretation of the reporting above, not reported fact.
The exploit works even when every security tool functions correctly, because the danger comes from an AI agent treating logged attacker text as a legitimate instruction rather than from any broken defense. That means a low attack-block rate offers no real protection when the agent itself can independently trigger high-impact actions like DNS changes. OWASP's LLM security lead argues the only real fix is separating an agent's ability to propose changes from its ability to approve them, via an external authorization gate.
- Tenet Security calls this attack pattern 'GhostJacking,' shown live at DEF CON 34.
- An AI agent read a blocked firewall log's attacker payload and used it to rewrite DNS settings with valid stored credentials.
- Experts recommend requiring a separate authorization step outside the AI model before any agent-proposed change can execute.
YubiKey 5 NFC Security Key — When an AI agent can propose a DNS change but shouldn't approve it, the approval step needs a human holding a hardware key. The YubiKey 5 NFC plugs into USB-A or taps via NFC to enforce phishing-resistant second-factor approval on cloud consoles and registrar accounts, so a planted prompt-injection payload can't push a change through on its own credentials.
See YubiKey 5 NFC Security Key on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: venturebeat.com, 2026-08-26
Published there as: “The fix for the AI agent that hijacked a company's DNS: it can propose the change, but it can't approve it”
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