A cloud-init security update has been released for Debian GNU/Linux 9 LTS to address an issue where unhashed password will be written to a world-readable local file.

DLA 2601-1: cloud-init security update

- -----------------------------------------------------------------------
Debian LTS Advisory DLA-2601-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Utkarsh Gupta
March 20, 2021   https://wiki.debian.org/LTS
- -----------------------------------------------------------------------

Package : cloud-init
Version : 0.7.9-2+deb9u1
CVE ID : CVE-2021-3429
Debian Bug : 985540

cloud-init has the ability to generate and set a randomized password
for system users. This functionality is enabled at runtime by
passing cloud-config data such as:

chpasswd:
list: |
user1:RANDOM

When used this way, cloud-init logs the raw, unhashed password to a
world-readable local file.

For Debian 9 stretch, this problem has been fixed in version
0.7.9-2+deb9u1.

We recommend that you upgrade your cloud-init packages.

For the detailed security status of cloud-init please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/cloud-init

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