🔐 Claude Mythos Shock

Hello, we are SecuLayer, a company specializing in AI-based cybersecurity solutions.​

This is the hottest security issue lately, right?
In relation to Claude Mythos, SecuLayer aims to thoroughly analyze the threat level of Claude Mythos and present a layered defense strategy that companies must have.

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📌 Key Points

The rapid advancement of AI is fundamentally shaking the paradigm of cybersecurity.
Generative AI has evolved from being used as tools for writing phishing emails or modifying malware to becoming 'autonomous hacking agents' that can independently explore vulnerabilities and conduct multi-stage hacking.

Recently, the 'Claude Mythos Preview' model from Anthropic, revealed through an evaluation by the UK AI Security Institute (AISI), has delivered a significant shock to the security industry.
It has been proven that AI can independently conduct complex corporate network penetration tests that human security experts used to perform over dozens of hours.

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What is Claude Mythos?

Claude Mythos is a cutting-edge AI model developed by the AI research company Anthropic.
It demonstrates performance that far surpasses the previous generation's top-performing model, Claude Opus 4.6, particularly in cybersecurity and attack capabilities.

According to an independent evaluation report led by the UK government-affiliated AI Security Institute (AISI), the Mythos Preview version has been confirmed to possess autonomy to select tools, plan continuous attack scenarios, and bypass defense logic in order to achieve given objectives, going beyond simple code analysis or vulnerability scanning.
This suggests that if an attacker provides at least minimal prompts, the AI can automate the process of reconnaissance and ultimately taking control of the target network.

Examples of the 'Mythos Shock'

✅ Example 1. Achieving a 73% Success Rate in Expert-Level CTF Challenges

Previous leading AI models recorded a success rate close to 0% in Capture-the-Flag (CTF) challenges at the level of information security experts. However, the Claude Mythos Preview achieved an overwhelming success rate of 73%.
This indicates that AI has acquired reverse engineering, decryption, and system exploit capabilities at the level of human experts.

✅ Example 2. Successful 32-Step Corporate Network Penetration Simulation (TLO)

The most notable result is the corporate network attack simulation called 'The Last Ones (TLO)'.
This test, consisting of a total of 32 steps from initial reconnaissance to full network takeover, takes human security experts about 20 hours to complete. The Mythos Preview achieved full success (100% takeover) in 3 out of 10 autonomous attempts.
Additionally, it completed an average of 22 steps, demonstrating a significant improvement in penetration persistence compared to the previous model (Opus 4.6), which only completed 16 steps.

✅ Example 3. Why Organizations with Weak Defenses Are at Greater Risk

AISI's evaluation particularly warns that the gap in defensive capabilities leads to a gap in damage.
Internet-exposed assets with delayed patches, default administrator accounts, excessive permissions, insufficient logging, and environments without EDR/SIEM are very good targets for autonomous AI.
Since the Mythos Preview has also shown scalability, improving performance as more computing resources are applied, the cost-effectiveness for attackers increases, making it highly likely that organizations with weak security fundamentals will be exposed in succession.

Security Implications: Organizations with Weak Defenses Are at Greater Risk

The implications of this advancement in AI are clear.
Small to medium-sized enterprises or organizations that neglect legacy systems without basic security controls can become immediate victims of autonomous AI attacks.
In environments lacking modern security solutions like active monitoring systems or EDR/SIEM, AI can ravage networks at speeds dozens of times faster than humans.

[Figure 1] The Need for Strengthening AI Security Governance in Financial and Enterprise Environments After the Mythos Shock (Source: Related Infographic)

As seen in the figure above, in financial/enterprise environments where regulations on network separation are being relaxed and the introduction of AI in internal networks is accelerating, a mutual AI security strategy is required to protect AI itself while also preventing attacks that exploit AI.

Response Strategy 1: Administrative Security Response

SecuLayer recommends establishing a solid administrative control foundation before introducing technology to combat AI threats.

Response Strategy 2: Technical Response Measures (7-Layer Response System)

A single security solution cannot prevent multi-stage attacks that learn evasion techniques like Mythos.
SecuLayer proposes a '7-Layer Defense in Depth System' that layers defense mechanisms from the attack surface to incident response (IR).

SecuLayer Recommendations

Conclusion​

Cybersecurity has now transformed into a 'battle of AI against AI'.
The performance demonstrated by Claude Mythos suggests that AI is no longer just a simple auxiliary tool but can serve as an automation engine for the attack chain that includes reconnaissance, penetration, proliferation, and achieving objectives.

However, this threat does not operate uniformly across all organizations.
Ultimately, the first to be at risk are environments with weak basic controls, while organizations equipped with fundamentals such as regular patching, access control, comprehensive logging, EDR/SIEM, and backup integrity can significantly reduce the scope of damage.

SecuLayer believes that establishing actionable systems is more important than fear marketing.
Assessing the current situation based on the 7-Layer Response System, which connects asset identification to automated recovery, and prioritizing the supplementation of missing controls is the most realistic alternative.

Source / References

1.    SK Shieldus, Cybersecurity Evolving with AI, Now is the Era of 'AI Threat vs AI Security'

2.    Summary of UK AISI Evaluation - PDF related to Claude Mythos Preview

3.    AI Drive provided image materials (Mythos Shock Infographic)