Title

RHEL 8 must restrict usage of ptrace to descendant processes. (Cat II impact)

Discussion

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. The sysctl --system command will load settings from all system configuration files. All configuration files are sorted by their filename in lexicographic order, regardless of which of the directories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name will take precedence. Files are read from directories in the following list from top to bottom. Once a file of a given filename is loaded, any file of the same name in subsequent directories is ignored. /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf

Check Content

Verify RHEL 8 restricts usage of ptrace to descendant processes with the following commands: $ sudo sysctl kernel.yama.ptrace_scope kernel.yama.ptrace_scope = 1 If the returned line does not have a value of "1", or a line is not returned, this is a finding. Check that the configuration files are present to enable this network parameter. $ sudo grep -r kernel.yama.ptrace_scope /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf /etc/sysctl.d/99-sysctl.conf: kernel.yama.ptrace_scope = 1 If "kernel.yama.ptrace_scope" is not set to "1", is missing or commented out, this is a finding. If conflicting results are returned, this is a finding.

Fix Text

Configure RHEL 8 to restrict usage of ptrace to descendant processes by adding the following line to a file, in the "/etc/sysctl.d" directory: kernel.yama.ptrace_scope = 1 Remove any configurations that conflict with the above from the following locations: /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command: $ sudo sysctl --system

Additional Identifiers

Rule ID: SV-230546r858824_rule

Vulnerability ID: V-230546

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

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