Ledger fixes vulnerability in Ethereum app’s signing flows

Ledger quietly patched a vulnerability in its Ethereum hardware wallet app on August 12 that could have allowed a malicious decentralized application to swap out a legitimate transaction for a harmful one mid-signing. The fix shipped in Ethereum app version 1.22.2, but the company said almost nothing about it publicly until a security researcher forced the conversation. The bug involved an APDU command race condition, a type of flaw where competing instructions can arrive at the device in a sequence that tricks the signing process. In practical terms, a user could have thought they were approving a small token transfer while actually authorizing unlimited token approvals to an attacker-controlled address. How the vulnerability worked APDU stands for Application Protocol Data Unit, essentially the language that software on your computer uses to talk to the secure chip inside a Ledger device. During what Ledger calls “clear signing” flows, where the device displays human-readable transaction details on its screen, the race condition could have allowed a second, malicious APDU command to slip in and replace the original transaction data. The attack would have required a compromised or...