He Wrote the 27-Year-Old Bug Mythos Found. Then Proved Mythos Wasn’t Necessary | Neils Provos | S2E4

Item: He Wrote the 27-Year-Old Bug Mythos Found. Then Proved Mythos Wasn’t Necessary | Neils Provos | S2E4
Rating: 4
Author: PostSingularity Institute

by Eva Benn

Applied Sciences & Engineering Computing & Cybersecurity URComputer security URHComputer fraud and hacking

🎙 Eva Benn 👥 101K 📅 August 10, 2026 ⏱ 49 min 👁 6K 📄 interview 🧭 2026-08-16

Available in: English (current) Français

Keywords

AI agentsvulnerability discoveryIronCurtainsecurity invariantsprompt injection

Summary

In this episode of Security Mondays, host Eva Benn interviews Niels Provos, a distinguished security engineer and creator of IronCurtain. Provos discusses his role in committing a 27-year-old OpenBSD bug that was recently found by Anthropic’s Mythos model. He explains how he replicated the discovery using his own agentic workflow with less capable models, demonstrating that vulnerability discovery is an orchestration problem rather than a frontier model problem. The conversation covers the decomposition of the vulnerability discovery process, the challenges of model refusals and rate limits, and the advantages attackers have with uncensored open-weight models. Provos also introduces IronCurtain, an open-source security framework for AI agents that enforces deterministic policies to mitigate risks like prompt injection and ambient authority. He advocates for treating AI agents as untrusted and implementing security invariants—controls that eliminate entire attack classes. He shares an analysis of 70 real breaches where three controls could have stopped 65% of them. The episode concludes with a discussion on the AI dependency risk and the importance of scoping agent capabilities.

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Critical Evaluation

Value of the Information & Strength of the Argument

The value of the information is high, as it provides practical insights into AI-driven vulnerability discovery and agent security. Provos argues convincingly that the capability to find vulnerabilities is not exclusive to frontier models, supported by his reproducible workflow. He effectively breaks down the process into manageable steps, making it accessible. The argumentation is solid, grounded in his personal experience and open-source contributions. He also highlights the asymmetry between defenders and attackers, emphasizing the need for deterministic security policies. The discussion on security invariants is particularly valuable, offering a proactive approach to reducing breach impact.

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Title / Content Match

The title accurately reflects the content, focusing on the guest's role in the bug and his demonstration that frontier models are not necessary for vulnerability discovery.

Quality & Reliability

8/10

The interview features a distinguished security expert with a strong track record, and the claims are supported by reproducible open-source work and references to specific incidents. However, some assertions (e.g., the Grok Morse code story) are anecdotal and not independently verified.

Chapters

Cited Sources

IronCurtain GitHub repository — Open-source framework for AI agent security, discussed in the episode.
IronCurtain website — Official site for IronCurtain, providing documentation and details.
Finding Zero-Days with Any Model — Article by Niels Provos detailing his approach to vulnerability discovery with any model.
The Day After the Zero-Days — Follow-up article discussing the implications of the vulnerability discovery workflow.
The Day After the Zero-Days talk (Cloud Security Alliance AI Summit) — Video of a talk by Niels Provos on the same topic.
Security Blueprints — Website for Security Blueprints, where Provos researches security invariants.
Three invariants / 70-breach analysis — Analysis of 70 breaches showing three controls could stop 65%.
The Agent Perimeter Fallacy — Article discussing the fallacy of relying on agent perimeters for security.

Concurring Sources

Anthropic's Red Team report — The report that highlighted the Mythos finding, which the episode builds upon.

Dissenting Sources

Claims about frontier model necessity — Some may argue that frontier models are still necessary for complex vulnerability discovery, but Provos's demonstration challenges this.

External References

Contribution & Novelties

The episode provides a novel perspective on AI-driven vulnerability discovery, challenging the assumption that frontier models are necessary. Niels Provos’s demonstration that an orchestrated workflow with open-weight models can replicate findings is a significant contribution. The introduction of IronCurtain as a security-first agent runtime offers a practical solution for mitigating risks. The concept of security invariants, machine-enforced controls that eliminate attack classes, is a forward-thinking approach. The episode also highlights the asymmetry between defenders and attackers, urging organizations to adopt deterministic policies.

Pour aller plus loin :

Model Context Protocol (MCP) — The protocol used by IronCurtain to interface with agents, relevant for understanding the security layer.
Prompt injection — A key threat discussed, with OWASP providing an overview.
OpenBSD — The operating system where the 27-year-old bug was found, relevant for context.
Anthropic’s Mythos — The frontier model that originally found the bug, though not used in the reproduction.

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Radar Profile

The radar profile shows high scores in information quantity, quality, and reliability, with a slightly lower technical level, indicating the content is accessible yet substantive. The overall balance suggests a well-rounded and credible discussion.

Reliability 8/10

💬 Sur les 14 commentaires analysés, les spectateurs ont salué la clarté de l'explication et la pertinence des conseils pratiques, avec quelques demandes de précisions techniques supplémentaires.