Security Bulletin: A vulnerability has been identified in IBM Spectrum Scale where an unprivileged user could execute commands as root ( CVE-2020-4273)

Security Bulletin

Summary

A security vulnerability has been identified in all levels of IBM Spectrum Scale that could allow underprivileged attacker to execute commands as root. A fix for this vulnerability is available.

Vulnerability Details

CVEID: CVE-2020-4273
DESCRIPTION: IBM Spectrum Scale could allow a local unprivileged attacker with intimate knowledge of the enviornment to execute commands as root using specially crafted input.
CVSS Base score: 7.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/175977 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

Affected Product(s)	Version(s)
IBM Spectrum Scale	All

Remediation/Fixes

For IBM Spectrum Scale V5.0.0.0 through 5.0.4.2, apply V5.0.4.3 available from FixCentral at:

https://www.ibm.com/support/fixcentral/swg/selectFixes?parent=Software%20defined%20storage&product=ibm/StorageSoftware/IBM+Spectrum+Scale&release=5.0.4&platform=All&function=all

For IBM Spectrum Scale V4.2.0.0 through V4.2.3.20, apply V4.2.3.21 available from FixCentral at:

https://www.ibm.com/support/fixcentral/swg/selectFixes?parent=Software%20defined%20storage&product=ibm/StorageSoftware/IBM+Spectrum+Scale&release=4.2.3&platform=All&function=all

If you cannot apply the latest level of service, contact IBM Service for an efix:

- For IBM Spectrum Scale V5.0.0.0 through V5.0.4.2, reference APAR IJ23438

- For IBM Spectrum Scale V4.2.0.0 through V4.2.3.20, reference APAR IJ23426

Workarounds and Mitigations

Until the fixes can be applied, a workaround is to remove the setuid from the files in the /usr/lpp/mmfs/bin directory. Determine the set of files with setuid bit by running

ls -l /usr/lpp/mmfs/bin | grep r-s

Then reset the setuid bit for each such file by issuing this command on each file

chmod u-s file

Once the workaround is applied, a number of commands may no longer work when not invoked by unprivileged users, including:

mmchfileset
mmcrsnapshot
mmdelsnapshot
mmdf
mmedquota
mmgetacl
mmlsdisk
mmlsfileset
mmlsfs
mmlsmgr
mmlspolicy
mmlspool
mmlsquota
mmlssnapshot
mmputacl
mmsnapdir

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References

Complete CVSS v3 Guide
On-line Calculator v3

Off

Acknowledgement

The vulnerability was reported to IBM by Winston S

Change History

21 April 2020: Final version Published with updated APAR details

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.

Disclaimer

Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.

Document Location

Worldwide

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Tips

Security Bulletin: A vulnerability has been identified in IBM Spectrum Scale where an unprivileged user could execute commands as root ( CVE-2020-4273)