AI agents find $4.6M in blockchain smart contract exploits
68 comments
·December 1, 2025samuelknight
vngzs
How do you manage to coax public production models into developing exploits or otherwise attacking systems? My experience has been extremely mixed, and I can't imagine it boding well for a pentesting tools startup to have end-users face responses like "I'm sorry, but I can't assist you in developing exploits."
dboreham
I've had similar experience using LLMs for static analysis of code looking for security vulnerabilities, but I'm not sure it makes sense for me to found a start up around that "product". Reason being that the technology with the moat isn't mine -- it belongs to Anthropic. Actually it may not even belong to them, probably it belongs to whoever owns the training data they feed their models. Definitely not me though. Curious to hear your thoughts on that. Is the idea to just try for light speed and exit before the market figures this out?
null
apercu
That’s 100% why I haven’t done this - we’ve seen the movie where people build a business around someone else’s product and then the api gets disabled or the prime uses your product as market research and replaces you.
tharkun__
Does that matter as long as you've made a few millions and just move on to do other fun stuff?
micromacrofoot
wild that so many companies these days consider the exit before they've even entered
NortySpock
It is considered prudent to write a business plan and do some market research if possible before starting a business.
rajamaka
Every company evaluates potential risks before starting.
VladVladikoff
I have a hotel software startup and if you are interested in showing me how good your agents are you can look us up at rook like the chess piece, hotel dot com
karlgkk
Is it rookhotel.com?
jesse__
To me, this reads a lot like : "Company raises $45 Billion, makes $200 on an Ethereum 0-day!"
stavros
Yeah but use of the models isn't limited to the company.
judgmentday
That graph is impenetrable. What is it even trying to say?
Also, in what way should any of its contents prove linear?
> yielding a maximum of $4.6 million in simulated stolen funds
Oh, so they are pointing their bots at already known exploited contracts. I guess that's a weaker headline.
codethief
Having watched this talk[0] about what it takes to succeed in the DARPA AIxCC competition[1] these days, this doesn't surprise me in the least.
ekjhgkejhgk
Can someone explain smart contracts to me?
Ok, I understand that it's a description in code of "if X happens, then state becomes Y". Like a contract but in code. But, someone has to input that X has happened. So is it not trivially manipulated by that person?
nrhrjrjrjtntbt
The pure (if you like) smart contacts do transactions. You give me 100 apple tokens and I give you 50 pear tokens. The contract ensures nothing else can happen.
They get more sophisticated e.g. automatic market makers. But same idea just swapping.
Voting is also possible e.g. release funds if there is a quorom. Who to release them to could be hard coded or part of the vote.
For external info from the real world e.g. "who got elected" you need an oracle. I.e. you trust someone not to lie and not to get hacked. You can fix the "someone" to a specific address but you still need to trust them.
wildzzz
That's a great explanation. I'm sure it's a lot deeper than that but I've never really understood the purpose. I'm not a crypto guy at all so it's nice hearing real world applications rather than just "stock market babble".
patrickaljord
Once a contract is deployed on the blockchain, its source code is immutable. So before using a contract, check if it gives permission to its deployer (or any address) to change any state at will.
Note that some contracts act as proxy to other contract and can be made to point to another code through a state change, if this is the case then you need to trust whoever can change the state to point to another contract. Such contract sometime have a timelock so that if such a change occurs, there's a delay before it is actually activated, which gives time to users to withdraw their funds if they do not trust the update.
If you are talking about Oracle contracts, if it's an oracle involving offchain data, then there will always be some trust involved, which is usually managed by having the offchain actors share the responsibility and staking some money with the risk to get slashed if they turn into bad actors. But again, offchain data oracles will always require some level of trust that would have to deal with in non-blockchain apps too.
pawelduda
Unless you know and trust person X, you don't want to authorize and interact with such contracts. Scammers will leave loopholes in code so they can, for example, grab all funds deposited to the contract.
Normal contracts that involve money operations would have safeguards that disallow the owner to touch balance that is not theirs. But there's billion of creative attack vectors to bypass that, either by that person X, or any 3rd party
momentmaker
blockchains are isolated environment where it can only know about data/states within itself.
if outside data is needed, then it needs something called an oracle, which delivers real-world and/or even other blockchain data to it.
you can learn more about oracle here: https://chain.link/education/blockchain-oracles
SV_BubbleTime
I’m convinced that there is a reason from blockchain, but it was like 10 years too early - OR - we’ve already passed the problem it solves and didn’t notice.
PunchyHamster
Well, technically DVCSes like git use "blockchain" (the repo, logically, is pretty much a chain of blocks that incorporate the hash of the previous blocks - just tree instead of linear dependency).
So we are already successfully using blockchain for decades just not as... currency provider.
Forward secure sealing (used in logging) also have similar idea
TheRoque
Not sure what you mean that "input that X has happened". You don't directly input the changes, instead, you call a function that creates that state change (or not, if it's invalid), by running its code. This code can include checks on who is the caller, it can check if you're the contract owner, if you're someone who already interacted with the contract (by checking previous state), or any hardcoded address etc.
Philpax
Yes, this is a problem (look up "the oracle problem"). My understanding is that the conventional solution is to rely on trusted third-party oracles that are outside of the control of the contract's participants and/or require consensus over multiple oracles.
px43
State is globally distributed, and smart contract code executes state transitions on that state. When someone submits a transaction with certain function parameters, anyone can verify that those parameters will lead to that exact state transition.
LikesPwsh
That's infamously known as the "Oracle Problem".
Blockchain can't handle external state.
Smart contracts abstract it a bit by having a trusted third party or an automated pricing mechanism, but both are fragile.
PunchyHamster
It's funny that it just re-invented stuff already used for old world finances, and just invented escrow with more moving parts while still requiring non-compromised 3rd party.
_pdp_
I am not surprised at all. I can already see self improving behaviour in our own work which means that the next logic step is self improving!
I know how this sounds but it seems to me, at least from my own vantage point, that things are moving towards more autonomous and more useful agents.
To be honest, I am excited that we are right in the middle of all of this!
krupan
No mention of Bitcoin. Exploiting ethereum smart contracts is nothing that new or exciting.
dtagames
No one has ever successfully manipulated Bitcoin and it doesn't offer smart contracts.
fragmede
> Important: To avoid potential real-world harm, our work only ever tested exploits in blockchain simulators. We never tested exploits on live blockchains and our work had no impact on real-world assets.
Well, that's no fun!
My favorite we're-living-in-a-cyberpunk-future story is the one where there was some bug in Ethereum or whatever, and there was a hacker going around stealing everybody's money, so then the good hackers had to go and steal everybody's money first, so they could give it back to them after the bug got fixed.
venturecruelty
"Money". The real cyberpunks would switch to anonymous, untraceable cash.
PunchyHamster
The whole ethereum fork was such a funny situation.
"Our currency is immutable and all, no banks or any law messing with your money"
"oh, but that contract that people got conned by need to be fixed, let's throw all promises into the trash and undo that"
"...so you just acted as bank or regulators would, because the Important People lost some money"
"essentially yeah"
ChadNauseam
The old version stayed around but (essentially) nobody wanted to use it. If they had, the forked version would be worthless. That is the difference. A cryptocurrency fork cannot succeed without the consent of the community. No one is compelled to use it the way that you are compelled to accept the decisions of a regulator.
ceejayoz
Well, the consent of some of the community.
Potentially far, far less than a majority of the community, even, considering it's not one person, one vote.
null
latenightcoding
when the core devs lose money, the rules change.
DennisP
It's been nine years since the chain split, which happened within the first year. No irregular changes have been made since then. Two major hacks caused over a hundred million dollars in losses to Parity, a company founded by one of the core devs. That dev lobbied heavily for rescue, and the community refused.
Bitcoin also made an irregular change, a year and a half into its history.
toomuchtodo
I’m surprised folks aren’t already grinding against smart contract security in prod with gen AI and agents. If they are, I suppose they are not being conspicuous by design. Power and GPU time goes in, exploits and crypto comes out.
px43
Of course they are, and they've been doing it since long before ChatGPT or any of that was a thing. Before it was more with classifiers and concolic execution engines, but it's only gotten way more advanced.
JimmyAustin
There are a great many of them, you just can't see them in the dark forest. https://www.paradigm.xyz/2020/08/ethereum-is-a-dark-forest
TheRoque
Check the prizes for the bug bounties in big smart contracts. The prizes are truly crazy, like Uniswap pays $15,000,000 for a critical vuln, and $1,000,000 for a high vuln. With that kind of money, I HIGHLY doubt there aren't people grinding against smart contracts as you say.
mschuster91
As soon as money in larger sums gets involved, the legal system will crack down hard on you if you are anywhere in the Western sphere of influence, easy as that.
In contrast, countries like North Korea, Russia, Iran - they all make bank on cryptocurrency shenanigans because they do not have to fear any repercussions.
yieldcrv
I mean they are, the only news here is that Anthropic isn't staffed by ignorant know-it-alls that wholesale dismiss the web3 development space like some other forum I know of
beefnugs
I couldnt find it in the article, how do they "assume" how many victims will fall to these contract exploits?
And to go further: if it costs $3500 in ai tokens, to fix a bug that could steal $3600, who should pay for that? Whos responsibility is it for "dumbass suckers who use other peoples buggy or purposefully malicious money based code" ?
At best this is another weird ad by anthropic, trying to say, hey why arent you changing the world with our stuff, pay up quick hurry
DennisP
Contracts themselves can hold funds. Usually a contract hack extracts the money it holds.
$3500 was the average cost per exploit they found. The cost to scan a contract averaged to $1.22. That cost should be paid by each contract's developers. Often they pay much more than that for security audits.
mightypirate
[dead]
mwkaufma
Says more about the relatively poor infosec on etherium contracts than about the absolute utility of pentesting LLMs.
px43
4.6M is not a lot, and these were old bugs that it found. Also, actually exploiting these bugs in the real world is often a lot harder than just finding the bug. Top bug hunters in the Ethereum space are absolutely using AI tooling to find bugs, but it's still a bit more complex than just blindly pointing an LLM at a test suite of known exploitable bugs.
Legend2440
According to the blogpost, these are fully autonomous exploits, not merely discovered bugs. The LLM's success was measured by much money it was able to extract:
>A second motivation for evaluating exploitation capabilities in dollars stolen rather than attack success rate (ASR) is that ASR ignores how effectively an agent can monetize a vulnerability once it finds one. Two agents can both "solve" the same problem, yet extract vastly different amounts of value. For example, on the benchmark problem "FPC", GPT-5 exploited $1.12M in simulated stolen funds, while Opus 4.5 exploited $3.5M. Opus 4.5 was substantially better at maximizing the revenue per exploit by systematically exploring and attacking many smart contracts affected by the same vulnerability.
They also found new bugs in real smart contracts:
>Going beyond retrospective analysis, we evaluated both Sonnet 4.5 and GPT-5 in simulation against 2,849 recently deployed contracts without any known vulnerabilities. Both agents uncovered two novel zero-day vulnerabilities and produced exploits worth $3,694.
TheRoque
True, I'd be curious to see if (and when) those contracts were compromised in the real world. Though they said they found 0 days, which implies some breaches were never found in the real world.
yieldcrv
> Important: To avoid potential real-world harm, our work only ever tested exploits in blockchain simulators. We never tested exploits on live blockchains and our work had no impact on real-world assets.
They left the booty out there, this is actually hilarious, driving a massive rush towards their models
user3939382
smart contracts the misnomer joke writes itself
yieldcrv
just means self executing, or more like domino triggered, in practice
quite a bit more advanced than contracts that do nothing on a sheet of paper, but the term is from 2012 or so when "smart" was appended to everything digital
AznHisoka
At first I read this as "fined $4.6M", and my first thought "Finally, AI is held accountable for their wrong actions!"
evanb
Careful what you wish for. Negating the predicate of "A COMPUTER CAN NEVER BE HELD ACCOUNTABLE. THEREFORE A COMPUTER MUST NEVER MAKE A MANAGEMENT DECISION" might open us up to the consequence.
My startup builds agents for penetration testing, and this is the bet we have been making for over a year when models started getting good at coding. There was a huge jump in capability from Sonnet 4 to Sonnet 4.5. We are still internally testing Opus 4.5, which is the first version of Opus priced low enough to use in production. It's very clever and we are re-designing our benchmark systems because it's saturating the test cases.