PyPI · linuxfabrik-lib
Linuxfabrik Monitoring Plugins: Sudoers may be able to obtain privilege escalation via /usr/bin/apt-get arguments
In the Debian.sudoers file, apt-get is allowed for the nagios user. The full command including the arguments are not enforced and can therefore be choosen arbitrarily. This allows to easily get a root shell as the nagios user:
By choosing a particular argument, you can get (as a nagios user) a root shell:
sudo apt-get update -o APT::Update::Pre-Invoke::="/bin/sh"
Since the nagious user can use sudo to run apt-get as root, the resulting shell is also running as root.
The vulnerability is a local privilege escalation, impacting users who use the provided sudoers file. It requires that an attacker already compromised the nagios account (which is quite a high barrier to be honest).
Since only one place where apt-get is currently used (in deb-updates) was found, it should be enough to allow only the specific arguments used there.
Here an example how the line in the sudoers file could look like:
/usr/lib64/nagios/plugins/strongswan-connections,\
/usr/lib64/nagios/plugins/systemd-unit,\
/usr/bin/apt-get update --quiet 2
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Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.