runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc, netlink is used internally as a serialization system for specifying the relevant container configuration to the `C` portion of the code (responsible for the based namespace setup of containers). In all versions of runc prior to 1.0.3, the encoder did not handle the possibility of an integer overflow in the 16-bit length field for the byte array attribute type, meaning that a large enough malicious byte array attribute could result in the length overflowing and the attribute contents being parsed as netlink messages for container configuration. This vulnerability requires the attacker to have some control over the configuration of the container and would allow the attacker to bypass the namespace restrictions of the container by simply adding their own netlink payload which disables all namespaces. The main users impacted are those who allow untrusted images with untrusted configurations to run on their machines (such as with shared cloud infrastructure). runc version 1.0.3 contains a fix for this bug. As a workaround, one may try disallowing untrusted namespace paths from your container. It should be noted that untrusted namespace paths would allow the attacker to disable namespace protections entirely even in the absence of this bug.
CVE-2021-43784 - Medium Severity Vulnerability
CLI tool for spawning and running containers according to the OCI specification
Library home page: https://proxy.golang.org/github.com/opencontainers/runc/@v/v1.0.0-rc9.zip
Dependency Hierarchy: - github.com/google/cadvisor/container/common-v0.35.0 (Root Library) - github.com/google/cadvisor/container-v0.35.0 - github.com/google/cadvisor/container/docker-v0.35.0 - github.com/google/cadvisor/container/libcontainer-v0.35.0 - :x: **github.com/opencontainers/runc-v1.0.0-rc9** (Vulnerable Library)
Found in HEAD commit: 6e30df8c07a51f900077867824d3807dffb18045
Found in base branch: master
runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc, netlink is used internally as a serialization system for specifying the relevant container configuration to the `C` portion of the code (responsible for the based namespace setup of containers). In all versions of runc prior to 1.0.3, the encoder did not handle the possibility of an integer overflow in the 16-bit length field for the byte array attribute type, meaning that a large enough malicious byte array attribute could result in the length overflowing and the attribute contents being parsed as netlink messages for container configuration. This vulnerability requires the attacker to have some control over the configuration of the container and would allow the attacker to bypass the namespace restrictions of the container by simply adding their own netlink payload which disables all namespaces. The main users impacted are those who allow untrusted images with untrusted configurations to run on their machines (such as with shared cloud infrastructure). runc version 1.0.3 contains a fix for this bug. As a workaround, one may try disallowing untrusted namespace paths from your container. It should be noted that untrusted namespace paths would allow the attacker to disable namespace protections entirely even in the absence of this bug.
Publish Date: 2021-12-06
URL: CVE-2021-43784
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Network - Attack Complexity: High - Privileges Required: Low - User Interaction: None - Scope: Unchanged - Impact Metrics: - Confidentiality Impact: Low - Integrity Impact: Low - Availability Impact: Low
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://github.com/opencontainers/runc/security/advisories/GHSA-v95c-p5hm-xq8f
Release Date: 2021-12-06
Fix Resolution: v1.0.3
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