Anthropic Mythos: the model Anthropic decided not to release

Anthropic introduced Mythos Preview, one of the most advanced models in cybersecurity. However, instead of a full public release, access has been restricted due to potential risks associated with its use.

⚙️ What Mythos can do

Mythos is a specialized model focused on security, code analysis, and complex logical tasks. Internal tests showed that it can work with systems at a level comparable to experienced cybersecurity professionals.

The model doesn't just answer questions: it analyzes large codebases, identifies vulnerabilities, explains potential exploitation scenarios, and demonstrates how individual issues may be interconnected.

🔖 Test results

During testing, the model was applied to real-world challenges. It successfully identified vulnerabilities in complex systems, including some that had gone unnoticed for a long time. One of the most notable examples was the discovery of a vulnerability in OpenBSD that had existed for about 27 years.

A particularly significant capability of Mythos is its ability to combine knowledge: it can link multiple weak points into a single chain and demonstrate how they form a complete attack vector, effectively simulating an attacker's thought process.

❓ Why the model was not released

Anthropic explicitly cites dual-use concerns: the same capabilities that help defend systems could also be used to launch attacks. Tasks that previously required expert analysis can now be executed much faster.

This implies: 🔵faster vulnerability discovery; 🔵lower barriers to entry for attackers; 🔵an increase in both the number and sophistication of attacks.

For these reasons, the company decided to restrict access and not release the model publicly. Instead, Anthropic launched a closed testing program involving several companies and research teams, including Amazon, Apple, Google, and Microsoft.

The goal is to use the model in a controlled environment for vulnerability discovery, system testing, and preparation for a future in which such tools become widely available.

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