CCE-92643-6Platform: cpe:/o:ubuntu:ubuntu_linux:18.04 | Date: (C)2019-11-07 (M)2023-07-04 |
There are several options available to limit which users and group can access the system via SSH. It is recommended that at least one of the following options be leveraged:
AllowUsers
The AllowUsers variable gives the system administrator the option of allowing specific users to ssh into the system. The list consists of comma separated user names. Numeric userIDs are not recognized with this variable. If a system administrator wants to restrict user access further by only allowing the allowed users to log in from a particular host, the entry can be specified in the form of user@host.
AllowGroups
The AllowGroups variable gives the system administrator the option of allowing specific groups of users to ssh into the system. The list consists of comma separated user names. Numeric groupIDs are not recognized with this variable.
DenyUsers
The DenyUsers variable gives the system administrator the option of denying specific users to ssh into the system. The list consists of comma separated user names. Numeric userIDs are not recognized with this variable. If a system administrator wants to restrict user access further by specifically denying a users access from a particular host, the entry can be specified in the form of user@host.
DenyGroups
The DenyGroups variable gives the system administrator the option of denying specific groups of users to ssh into the system. The list consists of comma separated group names. Numeric groupIDs are not recognized with this variable.
Rationale:
Restricting which users can remotely access the system via SSH will help ensure that only authorized users access the system.
Parameter:
[user list separated by space]
Technical Mechanism:
Edit the /etc/ssh/sshd_config file to set one or more of the parameter as follows:
AllowUsers <userlist> AllowGroups <grouplist> DenyUsers <userlist> DenyGroups <grouplist>
CCSS Severity: | CCSS Metrics: |
CCSS Score : 9.8 | Attack Vector: NETWORK |
Exploit Score: 3.9 | Attack Complexity: LOW |
Impact Score: 5.9 | Privileges Required: NONE |
Severity: CRITICAL | User Interaction: NONE |
Vector: AV:N/AC:L/PR:N/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:51242 |