Client key replacement attack #40

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Skipper · 2026-03-29T09:53:37Z

Skipper commented

2026-03-29 09:53:37 +00:00

Suppose vault was created locally.
Useragent unseal the vault and disconnects / idles.

Malware could:

Open database
Rewrite pubkey of useragent
Connect with it and pass authentication
Do whatever

Proposed solutions:

Ask client for unseal password after passing challenge
Derive signing key from seal key inside the server and sign each pubkey entry with that key

First solution is more straightforward, but second is better in terms of UX.
useragent pubkey entry couldn't be verified before unseal, but this doesn't matter because vault is sealed either way and malicious client would need to know unseal password.

Suppose vault was created locally. Useragent unseal the vault and disconnects / idles. Malware could: 1. Open database 2. Rewrite pubkey of useragent 3. Connect with it and pass authentication 4. Do whatever Proposed solutions: 1. Ask client for unseal password after passing challenge 2. Derive signing key from seal key inside the server and sign each pubkey entry with that key First solution is more straightforward, but second is better in terms of UX. useragent pubkey entry couldn't be verified before unseal, but this doesn't matter because vault is sealed either way and malicious client would need to know unseal password.

Skipper added the

labels 2026-03-29 09:53:37 +00:00

CleverWild referenced a pull request that will close this issue

2026-03-29 22:17:39 +00:00