Security Bulletin: Multiple vulnerabilities in the Linux kernel affect IBM SAN Volume Controller, IBM Storwize, IBM Spectrum Virtualize and IBM FlashSystem products

Summary

Vulnerabilities in the Linux Kernel affect IBM SAN Volume Controller, IBM Storwize V7000, V5000, V5100, V3700 and V3500, IBM Spectrum Virtualize Software, IBM Spectrum Virtualize for Public Cloud and IBM FlashSystem V9000 and 9100 family products. The applicable vulnerabilities are CVE-2019-11477, CVE-2019-11478 and CVE-2019-11479.

Vulnerability Details

CVEID:CVE-2019-11479
**DESCRIPTION:**Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/162665 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:CVE-2019-11478
**DESCRIPTION:**Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/162664 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:CVE-2019-11477
**DESCRIPTION:**Jonathan Looney discovered that the TCP_SKB_CB(skb)->tcp_gso_segs value was subject to an integer overflow in the Linux kernel when handling TCP Selective Acknowledgments (SACKs). A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit 3b4929f65b0d8249f19a50245cd88ed1a2f78cff.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/162662 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

IBM SAN Volume Controller
IBM Storwize V7000
IBM Storwize V5000
IBM Storwize V5100
IBM Storwize V3700
IBM Storwize V3500
IBM FlashSystem V9000
IBM FlashSystem 9100 Family
IBM Spectrum Virtualize Software
IBM Spectrum Virtualize for Public Cloud

All products are affected when running supported versions 7.5 to 8.2.

Remediation/Fixes

IBM recommends that you fix this vulnerability by upgrading affected versions of IBM SAN Volume Controller, IBM Storwize V7000, V5000, V3700 and V3500, IBM Spectrum Virtualize Software, IBM Spectrum Virtualize for Public Cloud and IBM FlashSystem V9000 and 9100 family to the following code levels or higher:

7.8.1.11

8.2.1.6

8.3.0.0

Latest IBM SAN Volume Controller Code
Latest IBM Storwize V7000 Code
Latest IBM Storwize V5000 Code
Latest IBM Storwize V3700 Code
Latest IBM Storwize V3500 Code
Latest IBM FlashSystem V9000 Code
Latest IBM FlashSystem 9100 Family Code
Latest IBM Spectrum Virtualize Software
Latest IBM Spectrum Virtualize for Public Cloud

For the Storage Nodes of IBM FlashSystem V9000, please apply the fixes recommended in the IBM FlashSystem security bulletin for this issue.

For unsupported versions of the above products, IBM recommends upgrading to a fixed, supported version of code.

Workarounds and Mitigations

Although IBM recommends that you install a level of code with a fix for this vulnerability, you can mitigate, although not eliminate, your risk until you have done so by ensuring that all users who have access to the system are authenticated by another security system such as a firewall.