RHEL-09-213075 - RHEL 9 must disable access to network bpf system call from nonprivileged processes.

Information

Loading and accessing the packet filters programs and maps using the bpf() system call has the potential of revealing sensitive information about the kernel state.

Satisfies: SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

Solution

Configure the currently loaded kernel parameter to the secure setting:

$ sudo sysctl -w kernel.unprivileged_bpf_disabled=1

Configure RHEL 9 to prevent privilege escalation through the kernel by disabling access to the bpf syscall by adding the following line to a file in the "/etc/sysctl.d" directory:

kernel.unprivileged_bpf_disabled = 1

The system configuration files must be reloaded for the changes to take effect. To reload the contents of the files, run the following command:

$ sysctl --system

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_9_V2R3_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-2, CAT|II, CCI|CCI-001082, Rule-ID|SV-257810r1044869_rule, STIG-ID|RHEL-09-213075, Vuln-ID|V-257810

Plugin: Unix

Control ID: 818b05c432988fb7816958bb027051c3a32e4bafa468891e37ae5c70abf36788