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Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

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Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#11

Post by sanxiyn »

pants2 wrote: post #9
ray_v wrote: post #3

As my coworker succinctly put it, "nobody uses Firefox anymore." I don't know if hundreds of millions of people is exactly, "nobody" but I personally agree that open source software is just going to crush closed source for exactly the reasons we're seeing unfold in front of us; you can audit and correct incorrect behavior for the benefits of all.

For closed-source, I'd expect defenders to have a greater advantage because they can run Mythos on the source code, while attackers only get an opaque API/protocol to try messing with.

To some extent yes, but models are good at reverse engineering such that it isn't as great advantage as you might think.

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#13

Post by wookmaster »

ray_v wrote: post #3

As my coworker succinctly put it, "nobody uses Firefox anymore." I don't know if hundreds of millions of people is exactly, "nobody" but I personally agree that open source software is just going to crush closed source for exactly the reasons we're seeing unfold in front of us; you can audit and correct incorrect behavior for the benefits of all.

Idk Mozilla has its issues but I still primarily use Firefox and librewolf on my Linux desktop. I refuse to use chrome except in instances where necessary.

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#14

Post by bvisness »

yborg wrote: post #4

What they did not say is how many of these vulnerabilities were addressed by LLM-created fixes, if any.

I can only speak for SpiderMonkey, as that’s the team I’m on, but we humans are definitely writing and reviewing the patches for these bugs. Sometimes the AI suggestions are good, often they’re not, and we never send off a fix for a security bug unless we thoroughly understand the problem and have assessed its severity ourselves.

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#16

Post by mccr8 »

lefty2 wrote: post #15

I wonder how many false positives there were. Typically this types of static analysis tools come up with a ton of potential bugs, but only a few of them are actual bugs.

The basic technique (as has been publicly described by Anthropic) is you ask one agent to come up with a test case that triggers, say, an ASan use-after-free. Then you have a second agent that validates the test case. This eliminates a lot of false positives. It gets a little tricky when you allow the first agent to modify the code, which is necessary for things like sandbox escapes where you want to demonstrate that sending bad IPC causes problems.

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#17

Post by ygjb »

mccr8 wrote: post #16
lefty2 wrote: post #15

I wonder how many false positives there were. Typically this types of static analysis tools come up with a ton of potential bugs, but only a few of them are actual bugs.

The basic technique (as has been publicly described by Anthropic) is you ask one agent to come up with a test case that triggers, say, an ASan use-after-free. Then you have a second agent that validates the test case. This eliminates a lot of false positives. It gets a little tricky when you allow the first agent to modify the code, which is necessary for things like sandbox escapes where you want to demonstrate that…

And the following part that is more important is the agent that attempts the fix in code, the agent that tests the fix and reports on perfomance and functional impacts, and the agent the triggers the build and release to production.

Everything up to finding and validating the bug is a huge win in vuln/exploit development, everything after validating the bug is a huge win for defensive security and a massive gap until the tools are generally available :S

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#18

Post by ygjb »

pants2 wrote: post #9
ray_v wrote: post #3

As my coworker succinctly put it, "nobody uses Firefox anymore." I don't know if hundreds of millions of people is exactly, "nobody" but I personally agree that open source software is just going to crush closed source for exactly the reasons we're seeing unfold in front of us; you can audit and correct incorrect behavior for the benefits of all.

For closed-source, I'd expect defenders to have a greater advantage because they can run Mythos on the source code, while attackers only get an opaque API/protocol to try messing with.

There is definitely a closed-source defender advantage where an attacker doesn't have access to the code, binary, or environment that can be instrumented (so basically, running in the cloud), but there have been several very effective technical demonstrations of LLM guided or agentic approaches to assessing the security of closed source tools, and I have had some successes personally using LLMs with tool use to manage binary analysis tools to perform reverse engineering of closed source packages.

For many attack scenarios the boundary is really if you can establish an effective canary or oracle for determining if a change in input results in a change in output, once you have that, it's simply a matter of scaling your testing or attack (for fuzzing, for blind injection, or any other number of attacks that depend on getting signal from a service).

Re: Mozilla Used Anthropic's Mythos to Find and Fix 271 Bugs in Firefox

#19

Post by totallyrandom__ »

Anthropic said they used 1000 agents worth $20k of token to discover "several dozens" of vulnerabilities in OpenBSD, of which only one was cool enough to mention it and brag about. That's not including the cost of 196 reviewers they also used.

The question is, if Firefox was given $20k worth of credit to find these vulnerabilities, how many vulnerabilities could have been discovered by paying that much money to security researchers who wouldn't have needed additional reviewers?

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