Farcaster is a social media application built on top of the Farcaster protocol, a decentralized social network. Farcaster itself is a blockchain-based protocol that enables the creation and connection of social apps. Essentially, Farcaster is a specific social app that leverages the Farcaster protocol to offer a decentralized social experience

Redirecting users to malicious websites (open redirect)

Injecting/modifying the static content on the target application without JavaScript (persistent), such as:
- HTML injection without JavaScript
- Replacing existing text with arbitrary text
- Arbitrary file uploads, etc.

Changing sensitive details of other users (including modifying browser local storage) without already-connected wallet interaction and with up to one click of user interaction, such as:
- Email
- Password of the victim etc.

Subdomain takeover without already-connected wallet interaction

Changing non-sensitive details of other users (including modifying browser local storage) without already-connected wallet interaction and with up to one click of user interaction, such as:
- Changing the first/last name of user
- Enabling/disabling notifications

Injecting/modifying the static content on the target application without JavaScript (reflected), such as:
- Reflected HTML Injection
- Loading external site data

Execute arbitrary system commands

Retrieve sensitive data/files from a running server, such as:
- /etc/shadow
- database passwords
- blockchain keys (this does not include non-sensitive environment variables, open source code, or usernames)

Taking and/modifying authenticated actions (with or without blockchain state interaction) on behalf of other users without any interaction by that user, such as:
- Changing registration information
- Commenting
- Voting
- Making trades
- Withdrawals, etc.

Theft of a user session through a single user interaction.

Subdomain takeover with already-connected wallet interaction

Direct theft of user funds

Malicious interactions with an already-connected wallet, such as:
- Modifying transaction arguments or parameters
- Substituting contract addresses
- Submitting malicious transactions

Bypassing the recovery process to gain control of the Farcaster wallet

Sitewide Service Disruption: Intentional disruption of core services sitewide, affecting multiple users.

Improperly disclosing confidential user information, such as:  Email address Phone number Physical address, etc.

Changing details of other users with significant user interaction.

Taking over broken or expired outgoing links, such as:  Social media handles, etc.

Farcaster Codebase

Documentation and further resources

Payouts are handled by the Farcaster team directly and are denominated in **USD**. However, payments are done in **USDC** on **Ethereum**.

The calculation of the net amount rewarded is based on the average price between CoinMarketCap.com and CoinGecko.com at the time the bug report was submitted. No adjustments are made based on liquidity availability.