Discourse is an open source platform for community discussion. In affected versions by creating replacement words with an almost unlimited number of characters, a moderator can reduce the availability of a Discourse instance. This issue has been addressed in stable version 3.2.3 and in current betas. Users are advised to upgrade. Users unable to upgrade may manually remove the long watched words either via SQL or Rails console.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Discourse | Discourse | * | 3.3.0 (excluding) |
| Discourse | Discourse | * | 3.3.2 (excluding) |
| Discourse | Discourse | 3.3.0-beta1 (including) | 3.3.0-beta1 (including) |
| Discourse | Discourse | 3.3.0-beta2 (including) | 3.3.0-beta2 (including) |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.