ESB-2018.1552 - [Appliance] F5 products: Denial of service - Existing account 2018-05-22

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             AUSCERT External Security Bulletin Redistribution

            K17403481: Linux kernel vulnerability CVE-2018-8897
                                22 May 2018


        AusCERT Security Bulletin Summary

Product:           F5 products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-8897  

Reference:         ASB-2018.0107

Original Bulletin:

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K17403481: Linux kernel vulnerability CVE-2018-8897

Security Advisory

Original Publication Date: May 15, 2018
Updated Date: May 22, 2018

Security Advisory Description

A statement in the System Programming Guide of the Intel 64 and IA-32
Architectures Software Developer's Manual (SDM) was mishandled in the
development of some or all operating-system kernels, resulting in unexpected
behavior for #DB exceptions that are deferred by MOV SS or POP SS, as
demonstrated by (for example) privilege escalation in Windows, macOS, some Xen
configurations, or FreeBSD, or a Linux kernel crash. The MOV to SS and POP SS
instructions inhibit interrupts (including NMIs), data breakpoints, and single
step trap exceptions until the instruction boundary following the next
instruction (SDM Vol. 3A; section 6.8.3). (The inhibited data breakpoints are
those on memory accessed by the MOV to SS or POP to SS instruction itself.)
Note that debug exceptions are not inhibited by the interrupt enable
(EFLAGS.IF) system flag (SDM Vol. 3A; section 2.3). If the instruction
following the MOV to SS or POP to SS instruction is an instruction like
SYSCALL, SYSENTER, INT 3, etc. that transfers control to the operating system
at CPL < 3, the debug exception is delivered after the transfer to CPL < 3 is
complete. OS kernels may not expect this order of events and may therefore
experience unexpected behavior when it occurs. (CVE-2018-8897)


This vulnerability allows for a disruption of service.

Security Advisory Status

F5 Product Development has assigned ID 719554 (BIG-IP), ID 719747 (BIG-IQ and
F5 iWorkflow), and ID 719744 (Enterprise Manager) to this vulnerability.
Additionally, BIG-IP iHealth may list Heuristic H17403481 on the Diagnostics >
Identified > Medium page.

To determine if your product and version have been evaluated for this
vulnerability, refer to the Applies to (see versions) box. To determine if your
release is known to be vulnerable, the components or features that are affected
by the vulnerability, and for information about releases or hotfixes that
address the vulnerability, refer to the following table.

|                   |      |Versions  |Fixes     |          |CVSSv3|Vulnerable|
|Product            |Branch|known to  |introduced|Severity  |score^|component |
|                   |      |be        |in        |          |1     |or feature|
|                   |      |vulnerable|          |          |      |          |
|BIG-IP (LTM, AAM,  |13.x  |13.0.0 -  |None      |          |      |          |
|AFM, Analytics,    |      |13.1.0    |          |          |      |          |
|APM, ASM, DNS, Edge+------+----------+----------+          |      |          |
|Gateway, FPS, GTM, |12.x  |12.1.0 -  |None      |Medium    |6.5   |Linux     |
|Link Controller,   |      |12.1.3    |          |          |      |Kernel    |
|PEM,               +------+----------+----------+          |      |          |
|WebAccelerator)    |11.x  |11.2.1 -  |None      |          |      |          |
|                   |      |11.6.3    |          |          |      |          |
|ARX                |6.x   |None      |Not       |Not       |None  |None      |
|                   |      |          |applicable|vulnerable|      |          |
|Enterprise Manager |3.x   |3.1.1     |None      |Medium    |6.5   |Linux     |
|                   |      |          |          |          |      |Kernel    |
|                   |5.x   |5.0.0 -   |None      |          |      |          |
|BIG-IQ Centralized |      |5.4.0     |          |Medium    |6.5   |Linux     |
|Management         +------+----------+----------+          |      |Kernel    |
|                   |4.x   |4.6.0     |None      |          |      |          |
|BIG-IQ Cloud and   |1.x   |1.0.0     |None      |Medium    |6.5   |Linux     |
|Orchestration      |      |          |          |          |      |Kernel    |
|F5 iWorkflow       |2.x   |2.0.2 -   |None      |Medium    |6.5   |Linux     |
|                   |      |2.3.0     |          |          |      |Kernel    |
|LineRate           |2.x   |None      |Not       |Not       |None  |None      |
|                   |      |          |applicable|vulnerable|      |          |
|                   |5.x   |5.0.0 -   |None      |          |      |          |
|Traffix SDC        |      |5.1.0     |          |Medium    |6.5   |Linux     |
|                   +------+----------+----------+          |      |Kernel    |
|                   |4.x   |4.4.0     |None      |          |      |          |

^1 The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.

Security Advisory Recommended Actions

If you are running a version listed in the Versions known to be vulnerable
column, you can eliminate this vulnerability by upgrading to a version listed
in the Fixes introduced in column. If the table lists only an older version
than what you are currently running, or does not list a non-vulnerable version,
then no upgrade candidate currently exists.



Supplemental Information

  o K51812227: Understanding Security Advisory versioning
  o K41942608: Overview of Security Advisory articles
  o K4602: Overview of the F5 security vulnerability response policy
  o K4918: Overview of the F5 critical issue hotfix policy
  o K9502: BIG-IP hotfix and point release matrix
  o K167: Downloading software and firmware from F5
  o K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents

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