Information
/etc/apt/auth.conf.d contains .conf files with credentials to access APT private repositories.
The /etc/apt/auth.conf.d directory contains APT .conf files which should have restricted access because they control how the package manager runs as root and may contain sensitive information. If writable or readable by non-root users, they could be altered to run malicious commands or expose credentials.
Solution
Run the following commands to set permissions on /etc/apt/auth.conf.d/ Uid and Gid are both 0/root and access is 0755 or more restrictive:
# chown root:root /etc/apt/auth.conf.d
# chmod u=rwx,g=rx,o=rx /etc/apt/auth.conf.d