Red Hat Security: Linux in Physical, Virtual, and Cloud

Instructions

1. Identify all Critical, Important, and Moderate security updates on the serverb machine.

   1. Log in to the serverb machine as the student user.

      [student@workstation ~]$ ssh student@serverb
      [student@serverb ~]$

   2. Change to the root user. Use student as the password.

      [student@serverb ~]$ sudo -i
      [sudo] password for student: student
      [root@serverb ~]#

   3. List the summary of the security updates. Among the 16 total security notices, eight are Important and eight are Moderate. The total security number might be different on your system.

      [root@serverb ~]# dnf updateinfo --security
      ...output omitted...
      Updates Information Summary: available
          16 Security notice(s)
               8 Important Security notice(s)
               8 Moderate Security notice(s)

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2. List the security-related packages that are available to update.

   [root@serverb ~]# dnf updateinfo list updates security
   ...output omitted...
   RHSA-2023:4354 Moderate/Sec.  curl-7.76.1-23.el9_2.2.x86_64
   ...output omitted...
   RHSA-2023:4354 Moderate/Sec.  libcurl-7.76.1-23.el9_2.2.x86_64
   ...output omitted...

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3. List the RHSAs with a Moderate severity rating.

   [root@serverb ~]# dnf updateinfo list updates security | grep Moderate
   RHSA-2023:4354 Moderate/Sec.  curl-7.76.1-23.el9_2.2.x86_64
   ...output omitted...
   RHSA-2023:4354 Moderate/Sec.  libcurl-7.76.1-23.el9_2.2.x86_64
   ...output omitted...

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4. View the information of the RHSA-2023:4354 RHSA to validate its content.

   [root@serverb ~]# dnf updateinfo info RHSA-2023:4354
   ...output omitted...
   ===============================================================================
     Moderate: curl security update
   ===============================================================================
     Update ID: RHSA-2023:4354
          Type: security
       Updated: 2023-08-01 03:58:15
          Bugs: 2196786 - CVE-2023-28321 curl: IDN wildcard match may lead to Improper Cerificate Validation
              : 2196793 - CVE-2023-28322 curl: more POST-after-PUT confusion
          CVEs: CVE-2023-28321
              : CVE-2023-28322
   Description: The curl packages provide the libcurl library and the curl utility for downloading files from servers using various protocols, including HTTP, FTP, and LDAP.
              :
              : Security Fix(es):
              :
              : * curl: IDN wildcard match may lead to Improper Cerificate Validation (CVE-2023-28321)
              :
              : * curl: more POST-after-PUT confusion (CVE-2023-28322)
              :
              : For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
      Severity: Moderate

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5. Use DNF and the RHSA ID to update the system with the necessary packages that provide the security fixes.

   [root@serverb ~]# dnf update --advisory RHSA-2023:4354
   ...output omitted...
   Dependencies resolved.
   ================================================================================
    Package
         Arch   Version           Repository                                  Size
   ================================================================================
   Upgrading:
    curl x86_64 7.76.1-23.el9_2.2 rhel-9.2-for-x86_64-baseos-additional-rpms 298 k
    libcurl
         x86_64 7.76.1-23.el9_2.2 rhel-9.2-for-x86_64-baseos-additional-rpms 286 k
   
   Transaction Summary
   ================================================================================
   Upgrade  2 Packages
   
   ...output omitted...
   Is this ok [y/N]: y
   ...output omitted...
   Upgraded:
     curl-7.76.1-23.el9_2.2.x86_64         libcurl-7.76.1-23.el9_2.2.x86_64
   
   Complete!

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6. List the summary of the security updates again to confirm that the number of notices is reduced for Moderate severity.

   [root@serverb ~]# dnf updateinfo --security
   ...output omitted...
   Updates Information Summary: available
       15 Security notice(s)
            8 Important Security notice(s)
            7 Moderate Security notice(s)

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7. Return to the workstation machine as the student user.

   [root@serverb ~]# logout
   [student@serverb ~]$ logout
   Connection to serverb closed.
   [student@workstation ~]$

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