GHSA-68vr-8f46-vc9f Username spoofing in OnionShare

• PyPI onionshare-cli: >= 2.3, < 2.5 → fixed in 2.5

Between September 26, 2021 and October 8, 2021, Radically Open Security conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's Red Team lab. This is an issue from that penetration test. • Vulnerability ID: OTF-005 • Vulnerability type: Improper Input Sanitization • Threat level: Low Description: It is possible to change the username to that of another chat participant with an additional space character at the end of the name string. Technical description: Assumed users in Chat: • Alice • Bob • Mallory 1. Mallory renames to `Alice `. 2. Mallory sends message as `Alice `. 3. Alice and Bob receive a message from Mallory disguised as `Alice `, which is hard to distinguish from the `Alice` in the web interface. Other (invisible) whitespace characters were found to be working as well. Impact: An adversary with access to the chat environment can use the rename feature to impersonate other participants by adding whitespace characters at the end of the username. Recommendation: • Remove non-visible characters from the username