
Defending Web3 from scams and exploits @Bitfinding Did binary hacking. Kind of skip web/cloud hacking. Doing blockchain hacking now.
Argentina
Joined March 2009
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Ledger write-up + PoC 👇
Offsets lovers: there’s a nice little trick to make the exploit fit the heap 👀
Normal user: keep calm and update
1/2 ⚠️ One action displayed. 257 authorized ⚠️
Our full write up is live: Signature overflow attacks on Ledger.
A Clear Signing bug broke a critical security property: What you see is what you sign.
🔎 Technical details + PoC:
bitfinding.com/blog/signatur…
feliam retweeted
On July 25, our team hacked OpenAI.
It took us less than 72 hours.
Two vulnerabilities chained together gave us access to ChatGPT and Codex accounts belonging to OpenAI employees. We demonstrated the impact with a harmless PR in OpenAI’s internal monorepo.
The full chain:
HEIF upload → libheif heap overflow → RCE → OpenAI SSO flaw → ChatGPT/Codex takeover → connected GitHub → internal PR.
OpenAI fixed the SSO issue roughly 14 hours after our report.
Research by @rootxharsh, @S1r1u5_ and @iamnoooob.
Full technical write-up:
hacktron.ai/blog/hacking-ope…
feliam retweeted
We are hiring a security researcher at @aave
Join us to review our smart contracts, build our AI-assisted tools, and help secure the ecosystem
You will work directly with me, have room to experiment, and develop new approaches as our industry evolves
aave.com/careers/protocol-se…
feliam retweeted
Researching weak wallet generation incidents we found that even when we could identify affected addresses, we had no way to warn the users who were using them.
Unlukey turns each known weak generation code into datasets that wallets can use to identify and warn users: coinspect.com/blog/introduci…
~we hacked ledger~ 🤣
The trusted screen showed a benign action. The signature enabled a Safe drain.
We reported privately, proved impact, retested releases, and waited for an installable fix.
After a week of Ledger disclosure drama, this is what doing it by the book looks like.
1/2 We helped Ledger identify and fix a High-severity Clear Signing vulnerability.
Ethereum app 1.19.0–1.22.2 is affected. Update to 1.22.3+.
Our advisory:
bitfinding.github.io/publica…
feliam retweeted
Onchain security is everyone’s problem and nobody’s job.
ETHSecurity Initiatives is how we are changing that.
Propose the work. Fund the work. Build the work.
initiatives.thedao.fund/
Ledger write-up + PoC 👇
Offsets lovers: there’s a nice little trick to make the exploit fit the heap 👀
Normal user: keep calm and update
1/2 ⚠️ One action displayed. 257 authorized ⚠️
Our full write up is live: Signature overflow attacks on Ledger.
A Clear Signing bug broke a critical security property: What you see is what you sign.
🔎 Technical details + PoC:
bitfinding.com/blog/signatur…
feliam retweeted
1/2 We helped Ledger identify and fix a High-severity Clear Signing vulnerability.
Ethereum app 1.19.0–1.22.2 is affected. Update to 1.22.3+.
Our advisory:
bitfinding.github.io/publica…
~we hacked ledger~ 🤣
The trusted screen showed a benign action. The signature enabled a Safe drain.
We reported privately, proved impact, retested releases, and waited for an installable fix.
After a week of Ledger disclosure drama, this is what doing it by the book looks like.
1/2 We helped Ledger identify and fix a High-severity Clear Signing vulnerability.
Ethereum app 1.19.0–1.22.2 is affected. Update to 1.22.3+.
Our advisory:
bitfinding.github.io/publica…
feliam retweeted
Replying to @ohyishi @OneKey_Anzen
No Ledger user was hacked.
What's described here is a lab reproduction of a vulnerability in an outdated version of the Ethereum app.
The issue was already identified through our security process and fixed in Ethereum app 1.22.2, released August 13, before this post. The security bulletin has been public since then: donjon.ledger.com/lsb/.
There is no evidence of exploitation in the wild.
A word on how this works, because it matters:
All software has bugs. Hardware wallets are no exception. That's why updateability is a core part of Ledger's security architecture: when a vulnerability is found, whether by our own Donjon team or by external researchers, we can patch every device in the field. A wallet that can't be updated can't be fixed.
This is a process we run continuously, not a one-off. We ship regular security updates, publish a security bulletin on the Ledger Donjon site donjon.ledger.com, and work with external researchers through our bug bounty program. That track record, finding, fixing, and disclosing, is what security maturity looks like. The alternative isn't wallets without bugs; it's wallets where you never hear about them.
What to do: update your firmware applications to the latest available and Ethereum app to 1.22.3+ via Ledger Wallet, and verify the app version on your device, not just the firmware. Apps and firmware update separately.
feliam retweeted
🚨 CRITICAL ETH SECURITY UPDATE
A critical vulnerability has been discovered in the Ethereum app on Ledger hardware wallets.
The flaw could allow a malicious application to alter ETH transaction details during signing without the change being visible on your Ledger device screen.
Fixed in Ethereum app v1.22.2
If you use Ledger for ETH or Ethereum assets:
• Update the Ethereum app to v1.22.2+
• Update Ledger Live
• Update your Ledger firmware
• Avoid signing transactions until everything is updated
If you hold ethereum:native on Ledger, update ASAP.
🚨Critical security update for LEDGER hardware wallets
A critical vulnerability has been identified in the Ethereum app on Ledger hardware wallets. It could allow a malicious application to alter the details of a transaction during signing, without this being visible on the device screen.
This has been fixed in Ethereum app version 1.22.2. If you use a Ledger device, please update ASAP
While you're in there, it's also good practice to make sure Ledger Live and your device firmware are fully up to date.
feliam retweeted
If you use Ledger for Ethereum, please update the Ethereum-app to v1.22.3. This is a new release.
Go update your Ledger. Again.
feliam retweeted
Anything over 30 days with a critical bug is negligence. It now takes hours to weaponize an exploit.
Shut down the bounty. Blacklist the project across other bug bounty platforms. Publicly advise users to withdraw funds.
No more free bugs.
I also got a reply in 6 minutes.
Leaving a High severity issue unfixed for 200+ days,
collecting submission fees, then marking later reports as duplicates… that's not a bug bounty program. That's a trap.
If a project refuses to patch,
they should be forced to pay double the submission fee
to every researcher who finds the same issue later. A report escalated 211 days ago is still open. Do these programs even deserve to run a bug bounty?
















