XBOW Tests Anthropic's Mythos Preview for Offensive Security

Michael Miller · 2026-06-09

### A New Tool for Finding Security Flaws Anthropic's Mythos Preview is turning heads in the offensive security world. XBOW, a leading antidetect browser, put it through its paces to see how well it can spot vulnerabilities. The results? Pretty impressive, especially when it comes to analyzing source code. Think of it like having a super-smart assistant that can scan thousands of lines of code in seconds, flagging potential weak spots that might take a human hours or days to find. ### What We Tested We looked at three main areas: - **Exploit discovery** – How quickly can Mythos find known and unknown vulnerabilities? - **Reverse engineering** – Can it break down complex code and figure out what it does? - **Live-site validation** – Does it work on real websites, not just in a lab? For each test, we used the same set of challenges that a human security researcher might face. The goal wasn't just to see if Mythos could find bugs, but how it compared to traditional methods. And spoiler alert: it did pretty well.  ### Source Code Analysis: Where Mythos Shines When it comes to reading raw code, Mythos is a beast. In our tests, it identified over 40% more vulnerability candidates than standard automated scanners. It's not just about quantity, either – the quality of the findings was solid. Many of the flagged issues were real, exploitable holes that could let an attacker in. Here's a quick example: we fed it a snippet of PHP code with a classic SQL injection flaw. Mythos not only found the injection point but also suggested the exact line numbers and the type of exploit that could work. That's the kind of detail that saves security teams hours of manual review. ### Reverse Engineering: A Mixed Bag Reverse engineering is tougher, even for AI. Mythos did well on simple binaries and scripts, but it struggled with heavily obfuscated code. For instance, when we gave it a packed executable, it missed some key logic paths. Still, it handled about 70% of the cases correctly, which is better than any off-the-shelf tool we've seen. > "Mythos is a game-changer for initial vulnerability discovery, but it's not a replacement for human intuition. Think of it as a force multiplier." – XBOW lead tester ### Live-Site Validation: Real-World Results We tested Mythos on a set of live, permission-granted test sites. The model was able to find cross-site scripting (XSS) and server-side request forgery (SSRF) vulnerabilities in under 10 minutes each. That's fast. But it also generated a few false positives – about 15% of its findings were not actually exploitable. That's a trade-off you have to accept when using AI for security. ### How XBOW Makes It Practical XBOW's antidetect browser adds a layer of stealth to these tests. By masking your digital fingerprint, you can run Mythos-powered scans without tipping off intrusion detection systems. That's huge for penetration testers who need to stay under the radar. The browser's built-in proxy rotation and user-agent spoofing mean you can test from multiple angles without leaving a trail. ### What This Means for Security Pros If you're in offensive security, this is a tool worth exploring. Mythos won't replace your team, but it can speed up the boring parts – like scanning thousands of lines of code for common mistakes. Use it to find the low-hanging fruit, then let your experts dig into the hard stuff. ### Final Thoughts Anthropic's Mythos Preview is a solid step forward for automated vulnerability discovery. It's not perfect, but it's better than anything else we've tested at scale. XBOW's integration makes it practical for real-world use. If you're serious about finding bugs before the bad guys do, give it a shot.