Incus blind SSRF via image import preflight HEAD request
Incus is an open source container and virtual machine manager. In versions prior to 7.0.0, the image import flow issues an outbound HEAD request to a user-supplied URL before validating the request against project restrictions such as restricted.images.servers. The imgPostURLInfo function constructs and sends a HEAD request directly from the attacker-supplied source URL to resolve image metadata, and this network interaction occurs before the flow reaches the point where the import would be rejected by policy. Although the actual image download is blocked by the project restriction, an authenticated user can coerce the daemon into making blin
Update of type field in restricted TLS certificate allows privilege escalation to cluster admin
In Canonical LXD versions 4.12 through 6.7, the doCertificateUpdate function in lxd/certificates.go does not validate the Type field when handling PUT/PATCH requests to /1.0/certificates/{fingerprint} for restricted TLS certificate users, allowing a remote authenticated attacker to escalate privileges to cluster admin.
Importing a crafted backup leads to project restriction bypass
In Canonical LXD before 6.8, the backup import path validates project restrictions against backup/index.yaml in the supplied tar archive but creates the instance from backup/container/backup.yaml, a separate file in the same archive that is never checked against project restrictions. An authenticated remote attacker with instance-creation permission in a restricted project can craft a backup archive where backup.yaml carries restricted settings such as security.privileged=true or raw.lxc directives, bypassing all project restriction enforcement and allowing full host compromise.
Incus is a system container and virtual machine manager. Incus instances have an option to provide credentials to systemd in the guest. For containers, this is handled through a shared directory. Prior to version 6.23.0, an attacker can set a configuration key named something like `systemd.credential.../../../../../../root/.bashrc` to cause Incus to write outside of the `credentials` directory associated with the container. This makes use of the fact that the Incus syntax for such credentials is `systemd.credential.XYZ` where `XYZ` can itself contain more periods. While it's not possible to read any data this way, it's possible to write to ar
Local Incus UI web server vulnerable to nuthentication bypass
Incus is a system container and virtual machine manager. Prior to version 6.23.0, the web server spawned by `incus webui` incorrectly validates the authentication token such that an invalid value will be accepted. `incus webui` runs a local web server on a random localhost port. For authentication, it provides the user with a URL containing an authentication token. When accessed with that token, Incus creates a cookie persisting that token without needing to include it in subsequent HTTP requests. While the Incus client correctly validates the value of the cookie, it does not correctly validate the token when passed int the URL.
This allows f
Incus vulnerable to arbitrary file read and write through pongo templates
Incus is a system container and virtual machine manager. Prior to version 6.23.0, instance template files can be used to cause arbitrary read or writes as root on the host server. Incus allows for pongo2 templates within instances which can be used at various times in the instance lifecycle to template files inside of the instance. This particular implementation of pongo2 within Incus allowed for file read/write but with the expectation that the pongo2 chroot feature would isolate all such access to the instance's filesystem. This was allowed such that a template could theoretically read a file and then generate a new version of said file. Un
Incus vulnerable to denial of source through crafted bucket backup file
Incus is a system container and virtual machine manager. Prior to version 6.23.0, a specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API. This does not impact any running workload, existing containers and virtual machines will keep operating. Version 6.23.0 fixes the issue.
Incus vulnerable to local privilege escalation through VM screenshot path
Incus is a system container and virtual machine manager. Incus provides an API to retrieve VM screenshots. That API relies on the use of a temporary file for QEMU to write the screenshot to which is then picked up and sent to the user prior to deletion. As versions prior to 6.23.0 use predictable paths under /tmp for this, an attacker with local access to the system can abuse this mechanism by creating their own symlinks ahead of time. On the vast majority of Linux systems, this will result in a "Permission denied" error when requesting a screenshot. That's because the Linux kernel has a security feature designed to block such attacks, `prote
Incus does not verify combined fingerprint when downloading images from simplestreams servers
Incus is a system container and virtual machine manager. Prior to version 6.23.0, a lack of validation of the image fingerprint when downloading from simplestreams image servers opens the door to image cache poisoning and under very narrow circumstances exposes other tenants to running attacker controlled images rather than the expected one. Version 6.23.0 patches the issue.
Incus container image templating arbitrary host file read and write
Incus is a system container and virtual machine manager. Versions 6.21.0 and below allow a user with the ability to launch a container with a custom image (e.g a member of the ‘incus’ group) to use directory traversal or symbolic links in the templating functionality to achieve host arbitrary file read, and host arbitrary file write. This ultimately results in arbitrary command execution on the host. When using an image with a metadata.yaml containing templates, both the source and target paths are not checked for symbolic links or directory traversal. This can also be exploited in IncusOS. A fix is planned for versions 6.0.6 and 6.21.0, but
Incus is a system container and virtual machine manager. In versions 6.20.0 and below, a user with the ability to launch a container with a custom YAML configuration (e.g a member of the ‘incus’ group) can create an environment variable containing newlines, which can be used to add additional configuration items in the container’s lxc.conf due to newline injection. This can allow adding arbitrary lifecycle hooks, ultimately resulting in arbitrary command execution on the host. Exploiting this issue on IncusOS requires a slight modification of the payload to change to a different writable directory for the validation step (e.g /tmp). This can
Incus vulnerable to local privilege escalation through custom storage volumes
Incus is a system container and virtual machine manager. An issue in versions prior to 6.0.6 and 6.19.0 affects any Incus user in an environment where an unprivileged user may have root access to a container with an attached custom storage volume that has the `security.shifted` property set to `true` as well as access to the host as an unprivileged user. The most common case for this would be systems using `incus-user` with the less privileged `incus` group to provide unprivileged users with an isolated restricted access to Incus. Such users may be able to create a custom storage volume with the necessary property (depending on kernel and fil
Incus vulnerable to antispoofing nftables firewall rule bypass on bridge networks with ACLs
Incus is a system container and virtual machine manager. When using an ACL on a device connected to a bridge, Incus versions 6.12 and 6.13generates nftables rules that partially bypass security options `security.mac_filtering`, `security.ipv4_filtering` and `security.ipv6_filtering`. This can lead to ARP spoofing on the bridge and to fully spoof another VM/container on the same bridge. Commit 254dfd2483ab8de39b47c2258b7f1cf0759231c8 contains a patch for the issue.
Incus vulnerable to DoS through antispoofing nftables firewall rule bypass on bridge networks with ACLs
Incus is a system container and virtual machine manager. When using an ACL on a device connected to a bridge, Incus version 6.12 and 6.13 generates nftables rules for local services (DHCP, DNS...) that partially bypass security options `security.mac_filtering`, `security.ipv4_filtering` and `security.ipv6_filtering`. This can lead to DHCP pool exhaustion and opens the door for other attacks. A patch is available at commit 2516fb19ad8428454cb4edfe70c0a5f0dc1da214.