GHSA-68vr-8f46-vc9f

Between September 26, 2021 and October 8, 2021, [Radically Open Security](https://www.radicallyopensecurity.com/) conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's [Red Team lab](https://www.opentech.fund/labs/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