CVE-2023-38487
Vulnérabilité moyenne dans hedgedoc (hedgedoc)
Description
HedgeDoc is software for creating real-time collaborative markdown notes. Prior to version 1.9.9, the API of HedgeDoc 1 can be used to create notes with an alias matching the ID of existing notes. The affected existing note can then not be accessed anymore and is effectively hidden by the new one. When the freeURL feature is enabled (by setting the `allowFreeURL` config option or the `CMD_ALLOW_FREEURL` environment variable to `true`), any user with the appropriate permissions can create a note by making a POST request to the `/new/<ALIAS>` API endpoint. The `<ALIAS>` parameter can be set to the ID of an existing note. HedgeDoc did not verify whether the provided `<ALIAS>` value corresponds to a valid ID of an existing note and always allowed creation of the new note. When a visitor tried to access the existing note, HedgeDoc will first search for a note with a matching alias before it searches using the ID, therefore only the new note can be accessed. Depending on the permission settings of the HedgeDoc instance, the issue can be exploited only by logged-in users or by all (including non-logged-in) users. The exploit requires knowledge of the ID of the target note. Attackers could use this issue to present a manipulated copy of the original note to the user, e.g. by replacing the links with malicious ones. Attackers can also use this issue to prevent access to the original note, causing a denial of service. No data is lost, as the original content of the affected notes is still present in the database. This issue was fixed in version 1.9.9. As a workaround, disabling freeURL mode prevents the exploitation of this issue. The impact can be limited by restricting freeURL note creation to trusted, logged-in users by enabling `requireFreeURLAuthentication`/`CMD_REQUIRE_FREEURL_AUTHENTICATION`.
Gravité et risque d'exploitation
CVE-2023-38487 obtient un score CVSS de 6.5/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.79 %, ce qui la place devant 55.6 % des CVE référencées.
Que faire ?
- Vérifiez si hedgedoc (versions < 1.9.9) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.