The SSH daemon must limit connections to a single session.

From VMware vSphere ESXi 6.0 Security Technical Implementation Guide

Part of SRG-OS-000480-VMM-002000

Associated with: CCI-000366

SV-77715r1_rule The SSH daemon must limit connections to a single session.

Vulnerability discussion

The SSH protocol has the ability to provide multiple sessions over a single connection without reauthentication. A compromised client could use this feature to establish additional sessions to a system without consent or knowledge of the user.

Check content

To verify the MaxSessions setting, run the following command: # grep -i "^MaxSessions" /etc/ssh/sshd_config If there is no output or the output is not exactly "MaxSessions 1", this is a finding.

Fix text

To set the MaxSessions setting, add or correct the following line in "/etc/ssh/sshd_config": MaxSessions 1

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