Apps with an embedded crypto wallet seed phrase

What this finding means

A BIP39 mnemonic is the twelve or twenty-four word phrase that represents the master key to a cryptocurrency wallet. It derives every private key the wallet holds, so it is not a credential that can be rotated: whoever has the phrase has the funds, permanently.

We have recorded a checksum-valid mnemonic embedded in 33 apps. This is the smallest category on the site and the one where a single true positive matters most.

Why the checksum matters to whether this is real

A BIP39 phrase is not an arbitrary list of words. The final word encodes a checksum over the preceding entropy, so only a small fraction of word sequences from the wordlist are valid phrases. Requiring the checksum to validate is what separates a real mnemonic from twelve English words that happen to appear near each other.

That still leaves one significant source of false positives, and it is the obvious one: test vectors. The BIP39 specification and nearly every wallet tutorial use the same handful of example phrases, and they are checksum-valid by construction. Those travel into apps through sample code and test fixtures.

We handle that the same way we handle library keys. A value appearing under three or more unrelated developers is treated as a shared artifact rather than one app's secret, which catches the documentation vectors while leaving a phrase unique to one app reported in full.

What to do if this is your app

• Move the funds first. A phrase that has shipped in a public binary is compromised, and no release can un-publish it.
• Generate a new wallet rather than attempting to secure the old one; the phrase cannot be rotated in place.
• If it was a test wallet, confirm it has never held real value, and keep test fixtures out of release builds so the question does not arise.
• Never derive a user's wallet on your servers or ship a wallet you generated; let the device generate the phrase and keep it in hardware-backed storage.
• Check your previous releases too, since those APKs remain downloadable.

What we store

The phrase is never stored. What is recorded is the fact that a checksum-valid mnemonic was present, a coarse length indicator and a non-reversible fingerprint used to deduplicate the finding and to recognise shared test vectors across apps.

We do not derive addresses from a phrase we find, and we do not query any chain to see whether a wallet holds a balance. Doing so would tell us whether the finding mattered, and it would also be the first step of taking the funds.