Shell Drop, audited through Anthropic’s cyber defence access
Shell Drop 5.2.7 is the first version of Shell Drop to be audited through Anthropic’s cyber defence access. The audit ran on Claude Fable 5.2 and covered the whole app: the iOS code, the SSH engine, and the terminal engine that draws everything a server sends to the screen.
An SSH app holds the keys to the servers people run their work on, so it is the kind of app that should be audited with the strongest tools available. Everything the audit found is fixed in 5.2.7.
How the audit ran
Reviewer agents went through the code one area at a time, looking for anything a hostile server, a tampered iCloud sync record or another app on the phone could misuse. Each lead was checked again by two separate verifiers before it counted as a finding.
The fixes then got an independent review of their own, which sent a handful back for a second round. After that I tested the build on a real iPhone, including the attacks the audit described, before it was submitted.
What changed in 5.2.7
- Saved passwords stay with their server. A saved password, key choice and key forwarding switch belong to the server they were set up for. If a connection synced from another device now points somewhere else, Shell Drop asks you to sign in again before anything is sent.
- Terminal images are handled more strictly. Images a server sends are accepted inline only, with size limits checked while they load, and a server can never ask the app to open a file on your phone.
- Private key export always asks for Face ID. Face ID approvals also end when the app goes to the background or the phone locks.
- Key forwarding ends with the connection. “Allow for this connection” on SSH agent forwarding ends when you disconnect, and only carries across an automatic reconnect to the same verified server.
- Uploads get unguessable names. Attached files and pasted images land under random names and never overwrite an existing file.
- Siri asks you to unlock first. The Connect to server shortcut needs the phone unlocked before it lists your connections.
- A closed tab stays closed. Closing a tab ends its connection for good.
What stays the same
Passwords and private keys still live only in this device’s Keychain and never sync to iCloud, and the app still collects no data. The first audit, from June, covers the parts of the design that were already in place, and the security and privacy page keeps the current picture.
Shell Drop 5.2.7 is with Apple for review and arrives on the App Store once it is approved. Shell Drop is free for iPhone, iPad and iPhone Duo, iOS 17+.