Arc before 2024-08-26 allows remote code execution in JavaScript boosts. Boosts that run JavaScript cannot be shared by default; however (because of misconfigured Firebase ACLs), it is possible to create or update a boost using another users ID. This installs the boost in the victims browser and runs arbitrary Javascript on that browser in a privileged context. NOTE: this is a no-action cloud vulnerability with zero affected users.
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
Access control involves the use of several protection mechanisms such as:
When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses: