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HistoryFeb 18, 2023 - 1:45 a.m.

Security Bulletin: Multiple Vulnerabilities in the Linux kernel affect the IBM FlashSystem models 840 and 900

2023-02-1801:45:50
www.ibm.com
33
linux kernel
ibm flashsystem
vulnerabilities
denial of service
code fixes

7.8 High

CVSS2

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

0.974 High

EPSS

Percentile

99.9%

Summary

There are vulnerabilities in the Linux kernel to which the IBM FlashSystem™ 840 and FlashSystem 900 are susceptible (CVE-2019-11477, CVE-2019-11478, and CVE-2019-11479). An exploit of these vulnerabilities could allow a remote attacker to cause a denial of service condition.

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-2019-11477
**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)

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)

Affected Products and Versions

Storage Node machine type and models (MTMs) affected:

  • 9846-AE1 and 9848-AE1
  • 9846-AE2 and 9848-AE2
  • 9846-AE3 and 9848-AE3

Supported storage node code versions which are affected

  • VRMFs prior to 1.5.2.6
  • VRMFs prior to 1.6.1.1

Remediation/Fixes

MTMs VRMF APAR Remediation/First Fix
FlashSystem 840 MTMs:

9840-AE1 and 9843-AE1

FlashSystem 900 MTMs:

9843-UF3, 9840-AE2, 9843-AE2, 9840-AE3, and 9843-AE3

|

Code fixes are now available, the minimum VRMF containing the fix depending on the code stream:

Fixed Code VRMF:

1.6 stream: 1.6.1.1

1.5 stream: 1.5.2.6

| N/A | FlashSystem 840 and FlashSystem 900 fixes are available at IBM’s Fix Central website.

Workarounds and Mitigations

Upgrade to a remediated code level.

Affected configurations

Vulners
Node
ibmflashsystem_900Matchany
OR
ibmflashsystem_900Matchany

7.8 High

CVSS2

Attack Vector

NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

0.974 High

EPSS

Percentile

99.9%