Debian 9 LTS: DLA-2789-1 Critical: Unsquashfs Directory Check Flaw

Richard Weinberger reported that unsquashfs in squashfs-tools, the tools
to create and extract Squashfs filesystems, does not check for duplicate
filenames within a directory. An attacker can take advantage of this flaw
for writing to arbitrary files to the filesystem if a malformed Squashfs
image is processed.


For Debian 9 stretch, this problem has been fixed in version
1:4.3-3+deb9u3.

We recommend that you upgrade your squashfs-tools packages.

For the detailed security status of squashfs-tools please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/squashfs-tools

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS