yum-security

yum-security is a plugin to the Red Hat Entreprise Linux package manager yum. It helps installing only security updates (RHSA) (as opposed to bug fixes (RHBA) or enhancements (RHEA)).
Explanation of RHSA, RHBA and RHEA advisories

RHEL 7 : yum-security is part of yum

RHEL 6 : yum install yum-plugin-security

    List all available erratas without installing them :

    yum updateinfo list available

    List all available security updates without installing them :

    yum updateinfo list security all
    yum updateinfo list sec

    List of the currently installed security updates :

    yum updateinfo list security installed

More examples are available in this Red Hat KB article

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Getting more details about Red Hat Security Advisories and related CVEs

Two links for an in-depth explanation regarding Red Hat backporting security fixes process as well as compatibility between Red Hat security advisories and Mitre CVEs.

Backporting Security Fixes

Red Hat and CVE compatibility

Red Hat provides free access to two databases for errata and for CVE referenced in Red Hat products :

Red Hat Product Errata database

Red Hat CVE Database

Upgrade a rpm package on a couple of servers with a quick one-liner in Ansible

Upgrade a rpm package on a couple of servers with a quick one-liner in Ansible :

export ANSIBLE_INVENTORY=servers_list
ansible all -b --ask-become-pass -m yum "name=bash state=latest"

servers_list is the text file listing your servers.
Using the ANSIBLE_INVENTORY variable overrides the use of a generate inventory.
This one-liner makes use of the yum Ansible module.
Running sudo commands is possible with these options -b and –ask-become-pass

Disabling TLS/SSL Birthday attacks on 64-bit block ciphers (SWEET32) in Apache in CentOS 7.2.1511

To disable TLS/SSL Birthday attacks on 64-bit block ciphers (SWEET32) in Apache in CentOS 7.2.15111, remove any DES-based ciphers in your Apache ssl configuration file :

[root@localhost:~]# cat /etc/httpd/conf.d/ssl.conf
SSLHonorCipherOrder on
SSLCipherSuite ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:RSA+AESGCM:RSA+AES:!aNULL:!MD5:!DSS

Make sure that your httpd config file syntax is OK :
[root@localhost:~]# apachectl configtest

Restart your web server :
[root@localhost:~]# systemctl restart httpd.service

Run a nmap scan with ssl-enum-ciphers script enabled :

[root@localhost:~]# nmap --script ssl-enum-ciphers -p 443 server_fqdn |grep 3DES

No DES-based ciphers should be displayed.