Security Bulletin: IBM Db2 Mirror for i is affected by CVE-2019-4536

Summary

IBM Db2 Mirror for i configurations may be subject to this security vulnerability. A PTF for IBM i 7.4 and remediation steps are available.

Vulnerability Details

CVEID: CVE-2019-4536 DESCRIPTION: IBM i 7.4 users who have done a Restore User Profile (RSTUSRPRF) on a system which has been configured with Db2 Mirror for i might have user profiles with elevated privileges caused by incorrect processing during a restore of multiple user profiles. A user with restore privileges could exploit this vulnerability to obtain elevated privileges on the restored system.
CVSS Base Score: 6.7
CVSS Temporal Score: See <https://exchange.xforce.ibmcloud.com/vulnerabilities/165592&gt; for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)

Affected Products and Versions

IBM i 7.4 with Db2 Mirror for i might be affected.

Remediation/Fixes

Take the following steps:

1. apply the PTF to IBM i 7.4, and
2. on systems with Db2 Mirror configured, review the scenarios below and take the steps if needed.

The IBM i PTF number is:

Release 7.4 – SI70767

<https://www-945.ibm.com/support/fixcentral/&gt;

If a Restore User Profile (RSTUSRPRF) has been done on an IBM i 7.4 system with Db2 Mirror configured prior to applying the PTF, remediation is required after applying the PTF for the following issues.

Issue #1: After the re-sync, there may be error entries on the Object Tracking List (OTL) for some system user profiles.

Issue #2: User profiles that were restored may have been given elevated privileges on both the source and target systems during the re-sync processing.

Remediation steps for both issues:

1. Delete any user profile error entries on the OTL that contain ‘RSTUSRPRF user_name’ in the Description field. Use the GUI to delete the entries.
2. Resume Db2 Mirror using the GUI.
3. Redo the RSTUSRPRF. You MUST use the same Save Security Data (SAVSECDTA) media as the original RSTUSRPRF. Do not use a SAVSECDTA media that was created after doing a RSTUSRPRF with Db2 Mirror configured and without the PTF applied.

There is no issue with RSTUSRPRF on a system that does not have Db2 Mirror configured.

**Important note:**IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None