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GHSA-4685-2x5r-65pj
No affected components available
Impact
Note: "Pebble" here refers to Canonical's service manager, not the Let's Encrypt ACME test server.
The API behind pebble pull, used to read files from the workload container by Juju charms, allows access from any user, instead of just admin. In Juju Kubernetes sidecar charms, Pebble and the charm run as root, so they have full access. But if another restricted unix user gains local access to the container host, they could hit the Pebble GET /v1/files?action=read API and would be allowed to read any file in the workload container, for example an ssh key or database password or other sensitive information. If there are ssh keys they could then potentially ssh into the workload, or if something like a database password they could log into the database.
Note that this requires local user access to the host machine. It seems unlikely that an attacker could gain this level of access in a Juju Kubernetes context, but if someone did and there's sensitive information in files accessible to Pebble, the consequences are bad.
To reproduce the issue, go back to the Pebble version in Juju 2.9 (5842ea68c9c7), do pebble run as root in one terminal window, then in another terminal window, as a regular user, use the pebble pull CLI. You will be able to pull any file as a regular user.
Patches
The original patch is commit https://github.com/canonical/pebble/commit/cd326225b9b0be067da7d8858e2c912078cbbbd5. There's also https://github.com/canonical/pebble/pull/406, which fixes this issue in more recent Pebble versions (that PR also fixes a separate issue we introduced more recently, but hasn't been released in Juju yet).
We released the fix in the following Pebble versions:
- https://github.com/canonical/pebble/releases/tag/v1.1.1
- https://github.com/canonical/pebble/releases/tag/v1.4.2
- https://github.com/canonical/pebble/releases/tag/v1.7.4
- https://github.com/canonical/pebble/releases/tag/v1.10.2
Juju will be releasing patch versions with this fix shortly:
- Juju 2.9.49 (Pebble v1.1.1)
- Juju 3.1.8 (Pebble v1.4.2)
- Juju 3.3.4 (Pebble v1.4.2)
- Juju 3.4.2 (Pebble v1.7.4)
- Juju 3.5.0 (Pebble v1.10.2)
References
- https://www.cve.org/CVERecord?id=CVE-2024-3250
The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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