CCE-91980-3Platform: cpe:/o:ubuntu:ubuntu_linux:16.04 | Date: (C)2018-07-09 (M)2023-07-04 |
There are a number of accounts provided with Ubuntu that are used to manage applications and are not intended to provide an interactive shell.
Rationale:
It is important to make sure that accounts that are not being used by regular users are locked to prevent them from being used to provide an interactive shell. By default Ubuntu set the password field for these accounts to an invalid string, but it is also recommended that the shell field in the password file be set to /usr/sbin/nologin. This prevents the account from potentially being used to run any commands.
Parameter:
[system accounts uid is less than 500/system accounts uid is less than 1000]
Technical Mechanism:
Accounts that have been locked are prohibited from running commands on the system. Such accounts are not able to login to the system nor are they able to use scheduled execution facilities such as cron. To make sure system accounts cannot be accessed, using the following script:
#!/bin/bash for user in `awk -F: ($3 500) {print $1 } /etc/passwd`; do if [ $user != root ]
then
/usr/sbin/usermod -L $user if [ $user != sync ] & [ $user != shutdown ] & [ $user != halt ] then
/usr/sbin/usermod -s /usr/sbin/nologin $user fi fi done
CCSS Severity: | CCSS Metrics: |
CCSS Score : 8.8 | Attack Vector: NETWORK |
Exploit Score: 2.8 | Attack Complexity: LOW |
Impact Score: 5.9 | Privileges Required: LOW |
Severity: HIGH | User Interaction: NONE |
Vector: AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | Scope: UNCHANGED |
| Confidentiality: HIGH |
| Integrity: HIGH |
| Availability: HIGH |
| |
References: Resource Id | Reference |
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SCAP Repo OVAL Definition | oval:org.secpod.oval:def:46241 |