CVE-2021-43784

Name
CVE-2021-43784
Description
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.
NVD Severity
medium
Other trackers
Mailing lists
Exploits
Forges
GitHub (code, issues), Aports (code, issues)

References

Type URI
MISC https://github.com/opencontainers/runc/commit/d72d057ba794164c3cce9451a00b72a78b25e1ae
MISC https://github.com/opencontainers/runc/commit/9c444070ec7bb83995dbc0185da68284da71c554
MISC https://github.com/opencontainers/runc/commit/f50369af4b571e358f20b139eea52d612eb55eed
CONFIRM https://github.com/opencontainers/runc/security/advisories/GHSA-v95c-p5hm-xq8f
MISC https://bugs.chromium.org/p/project-zero/issues/detail?id=2241
MLIST https://lists.debian.org/debian-lts-announce/2021/12/msg00005.html

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:linuxfoundation:runc:*:*:*:*:*:*:*:* runc >= None < 1.0.3

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
runc 3.15-community 1.0.2-r1 Jake Buchholz Göktürk <tomalok@gmail.com> possibly vulnerable