CVE-2020-15229

Singularity (an open source container platform) from version 3.1.1 through
3.6.3 has a vulnerability. Due to insecure handling of path traversal and
the lack of path sanitization within unsquashfs, it is possible to
overwrite/create any files on the host filesystem during the extraction
with a crafted squashfs filesystem. The extraction occurs automatically for
unprivileged (either installation or with allow setuid = no) run of
Singularity when a user attempt to run an image which is a local SIF image
or a single file containing a squashfs filesystem and is coming from remote
sources library:// or shub://. Image build is also impacted in a more
serious way as it can be used by a root user, allowing an attacker to
overwrite/create files leading to a system compromise, so far bootstrap
methods library, shub and localimage are triggering the squashfs
extraction. This issue is addressed in Singularity 3.6.4. All users are
advised to upgrade to 3.6.4 especially if they use Singularity mainly for
building image as root user. There is no solid workaround except to
temporary avoid to use unprivileged mode with single file images in favor
of sandbox images instead. Regarding image build, temporary avoid to build
from library and shub sources and as much as possible use --fakeroot
or a VM for that.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=972212&gt;