Security Bulletin: IBM RackSwitch firmware products are affected by TCP denial of service vulnarabilities

Summary

The IBM RackSwitch firmware products listed below have addressed the following TCP denial of service vulnerabilities.

Vulnerability Details

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)

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)

Affected Products and Versions

Product

|

Version

—|—

IBM RackSwitch G8052

|

7.11

IBM RackSwitch G8124/G8124E

|

7.11

IBM RackSwitch G8264

|

7.11

IBM RackSwitch G8264CS

|

7.8

IBM RackSwitch G8264T

|

7.9

IBM RackSwitch G8316

|

7.9

IBM RackSwitch G8332

|

7.7

Remediation/Fixes

Firmware fix versions are available on Fix Central: http://www.ibm.com/support/fixcentral/

Product

|

Fix Version

—|—

IBM RackSwitch G8052
(G8052_Image_7.11.16.0)

|

7.11.16.0

IBM RackSwitch G8124/G8124E
(G8124_G8124E_Image_7.11.16.0)

|

7.11.16.0

IBM RackSwitch G8264
(G8264_Image_7.11.16.0)

|

7.11.16.0

IBM RackSwitch G8264CS
(G8264CS_Image_7.8.24.0)

|

7.8.24.0

IBM RackSwitch G8264T
(G8264T_Image_7.9.26.0)

|

7.9.26.0

IBM RackSwitch G8316
(G8316_Image_7.9.26.0)

|

7.9.26.0

IBM RackSwitch G8332
(G8332_Image_7.7.32.0)

|

7.7.32.0

Workarounds and Mitigations

None