Insights

What does Claude Mythos and MDASH mean for cybersecurity?

Staying ahead of cybersecurity threats is a constant challenge for organisations and defenders. AI has made the pace of change even harder as attackers increasingly use AI to launch faster and more effective attacks (with less expertise).

More recently, AI is finding security vulnerabilities are a scale and speed that wasn’t possible. Anthropic’s Claude Mythos and Microsoft’s MDASH have reportedly uncovered thousands of previously unknown flaws, some hiding in widely used software for decades. In this article we outline the short-term and long-term picture and share our practical response for organisations that remains the same: get the cybersecurity basics right, as the window between a vulnerability being found and being exploited is only going to shrink.

What is Claude Mythos?

Mythos is one of the newest frontier models developed by Anthropic under their Claude family. Anthropic has claimed the model can outperform people at a range of hacking and cybersecurity tasks, and that it has surfaced long-dormant bugs in widely used code, including issues that have existed for decades and are readily exploitable.

Anthropic has not made Mythos publicly available. Instead, it has given a small group of major technology companies, including Microsoft and Google, access through an initiative codenamed Project Glasswing, positioned as “an effort to secure the world’s most critical software”.

What is Microsoft's MDASH?

MDASH, short for Multi-Model Agentic Scanning Harness, is Microsoft’s counterpart to Mythos and an early sign that this capability is industry-wide rather than vendor-specific. Microsoft reports that MDASH has already discovered sixteen previously unknown Windows vulnerabilities, including four critical remote code execution flaws in components such as the Windows kernel TCP/IP stack and the IKEv2 service, all fixed in a recent Patch Tuesday. You can read more on MDASH here.

What are the impacts of Mythos and MDASH?

The claims around these new frontier models represent a meaningful shift in cybersecurity, with thousands of previously unknown vulnerabilities reportedly identified across major operating systems and browsers, including flaws that have existed for decades. If those claims prove out, we are at the start of a busy and challenging period for software engineering and cybersecurity teams, even for well-maintained products and organisations with strong cyber hygiene, because well-chained exploits drawing on combinations of newly surfaced flaws represent a particularly high risk.

The concern deepens for organisations running older systems. It is not practical for every business to move to the latest and greatest overnight, and this category sits squarely in the firing line of a rapid and capable vulnerability exploitation pipeline.

It is worth saying clearly: it remains an “if” for now. The headline figures are largely self-reported, with limited independent verification, and there is legitimate debate around the extreme compute cost required to make these models perform at the levels claimed. The trend, however, is obvious. Project Glasswing partners have begun corroborating elements of the work, and at least one privilege escalation chain on macOS has already been attributed to techniques surfaced during Mythos testing. The wider picture is still emerging, and we are treating the claims as credible enough to plan against rather than as established fact.

Even so, the direction of travel is clear. Capabilities like this lower the barrier to offensive activity, and it is only a matter of time before equivalent tooling reaches less benign hands. Attackers no longer need deep expertise if AI can automate large parts of discovery and exploit construction, which puts organisations with weak security posture directly in the firing line.

The short-term picture is uncomfortable. Organisations already struggle to prioritise and patch the vulnerabilities they know about, and a sustained increase in disclosed findings will not make that easier. Patch Tuesdays will get heavier. Vendor support queues will lengthen. Scanner outputs will balloon. Security teams will face a familiar problem at a less familiar scale, trying to fix everything at once with finite hands and finite change windows. The asymmetry sharpens the pain: defenders have to patch all of it, attackers only need one chain to work. In the near term, the realistic expectation is more exposure, not less.

The longer-term picture is genuinely more hopeful, and it is worth holding on to. If models of this class are run continuously against code as it is written, reviewed, and deployed, the volume of latent vulnerabilities in production software should fall over time. Bugs that have hidden for decades get found and fixed once, rather than waiting to be rediscovered by an attacker years later. Vendors bake this capability into their secure development lifecycles. The patch treadmill slows. We end up in a materially more secure place than we are today, with fewer surprises and a tighter loop between code being written and code being trusted.

The honest framing is that this better future sits on the other side of the disruption, not in place of it. The industry will have to work through a period of real pressure on engineering teams, patching programmes, and incident response capacity before the benefits start to show. Organisations that invest now in the fundamentals will be the ones still standing when that turn comes.

What does this mean for partners and customers? 

For partners and customers, the practical posture is straightforward. Prioritise the basics that consistently fail under pressure, including asset visibility, patch velocity, identity hygiene, segmentation, and tested response. Invest in detection and response coverage that does not depend on knowing the specific vulnerability ahead of time, because the window between disclosure and exploitation is only going to compress further.

Looking for cybersecurity support?

Chorus Cyber is a managed security service provider (MSSP) delivering high-performing MDR and MXDR services through a channel partner model. We help organisations stay protected from cybersecurity threats with some of the fastest response times in the industry. If you’re looking for support with your cybersecurity, get in touch.