SB2021022805 - Debian update for docker.io
Published: February 28, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 4 secuirty vulnerabilities.
1) Insufficiently protected credentials (CVE-ID: CVE-2020-15157)
The vulnerability allows a remote attacker to gain access to sensitive information.
If a container image manifest in the OCI Image format or Docker Image V2 Schema 2 format includes a URL for the location of a specific image layer (otherwise known as a “foreign layer”), the default containerd resolver will follow that URL to attempt to download it. In v1.2.x the default containerd resolver will provide its authentication credentials if the server where the URL is located presents an HTTP 401 status code along with registry-specific HTTP headers.
If an attacker publishes a public image with a manifest that directs one of the layers to be fetched from a web server they control and they trick a user or system into pulling the image, they can obtain the credentials used for pulling that image. In some cases, this may be the user's username and password for the registry. In other cases, this may be the credentials attached to the cloud virtual instance which can grant access to other cloud resources in the account.
The default containerd resolver is used by the cri-containerd plugin (which can be used by Kubernetes), the ctr development tool, and other client programs that have explicitly linked against it.
2) Improper access control (CVE-ID: CVE-2020-15257)
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions. Access controls for the shim’s API socket verified that the connecting process had an effective UID of 0, but did not otherwise restrict access to the abstract Unix domain socket. This would allow malicious containers running in the same network namespace as the shim, with an effective UID of 0 but otherwise reduced privileges, to cause new processes to be run with elevated privileges.
3) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-21284)
The vulnerability allows a remote attacker to escalate privileges on the system.
The vulnerability exists due to application does not properly impose security restrictions when using the --userns-remap option. A remote authenticated attacker on the local network can send a specially crafted request and gain elevated privileges as root on the system.
4) Resource exhaustion (CVE-ID: CVE-2021-21285)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application does not properly control consumption of internal resources. A remote attacker can trick a victim to pull a specially crafted Docker image, trigger resource exhaustion and perform a denial of service (DoS) attack.
Remediation
Install update from vendor's website.