kernel security update (RHSA-2018-0008)

Original Release Date: January 5, 2018
Last Revised: June 14, 2018
Number: ASA-2018-005
Overall Severity Classification: Medium
Advisory Version: 3.0
Advisory Status: Interim

1. Overview:

The kernel packages contain the Linux kernel, the core of any Linux operating system.

An industry-wide issue was found in the way many modern microprocessor designs have implemented speculative execution of instructions (a commonly used performance optimization). There are three primary variants of the issue which differ in the way the speculative execution can be exploited.

Note: This issue is present in hardware and cannot be fully fixed via software update. The updated kernel packages provide software mitigation for this hardware issue at a cost of potential performance penalty. Please refer to References section for further information about this issue and the performance impact.

In this update mitigations for x86-64 architecture are provided.

Variant CVE-2017-5753 triggers the speculative execution by performing a bounds-check bypass. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall boundary and read privileged memory by conducting targeted cache side-channel attacks. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2017-5753 to this issue.

Variant CVE-2017-5715 triggers the speculative execution by utilizing branch target injection. It relies on the presence of a precisely-defined instruction sequence in the privileged code as well as the fact that memory accesses may cause allocation into the microprocessor's data cache even for speculatively executed instructions that never actually commit (retire). As a result, an unprivileged attacker could use this flaw to cross the syscall and guest/host boundaries and read privileged memory by conducting targeted cache side-channel attacks. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the nameCVE-2017-5715 to this issue.

Variant CVE-2017-5754 relies on the fact that, on impacted microprocessors, during speculative execution of instruction permission faults, exception generation triggered by a faulting access is suppressed until the retirement of the whole instruction block. In a combination with the fact that memory accesses may populate the cache even when the block is being dropped and never committed (executed), an unprivileged local attacker could use this flaw to read privileged (kernel space) memory by conducting targeted cache side-channel attacks. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2017-5754 to this issue.

Note: CVE-2017-5754 affects Intel x86-64 microprocessors. AMD x86-64 microprocessors are not affected by this issue.

More information about these vulnerabilities can be found in the security advisory issued by Red Hat:

2. Avaya System Products using a modified version of RHEL6 with affected packages installed:

For assessment and severity classification details refer to Section 3 of Avaya's Product Vulnerability Response Policy.
The "Resolution" column will be updated as fixes are made available. Please reference the "Information" column for any additional information regarding the affected product.

Product: Version(s): Resolution: Information:
Avaya Aura® Application Enablement Services 7.0.x 7.1.3 See PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.
Avaya Aura® Application Server 5300:
  • SIP Core
3.0 SP11 and later Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Breeze™ Platform 3.0 through 3.2.x 3.4.0.1 See PSN020353u for details on the remediaton and installation instructions.
Avaya CMS R17.x, R18 through R18.0.1 R18.0.2 See PSN027066u for details on the remediaton and installation instructions.
Avaya Aura® Communication Manager 7.0.x 7.1.3 See PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.
Avaya Aura® Communication Manager Messaging 7.0.x Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Aura® Conferencing 8.0.x Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Aura® Experience Portal 7.x 7.0.2, 7.1.0, 7.2.1 For 7.0.x see PSN004355u for details on the remediaton and installation instructions.
For 7.1.x see PSN004791u for details on the remediaton and installation instructions.
For 7.2.x see PSN005048u for details on the remediaton and installation instructions.
Avaya IP Office 9.x, 10.x Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Meeting Exchange 6.2 SP3 and later Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Aura® Messaging 7.0.x Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya one-X® Client Enablement Services 6.2.0 through 6.2.6 6.2.7 See PSN005155u for details on the remediaton and installation instructions.
Avaya Session Border Controller for Enterprise 6.3.x, 7.0.x, 7.1.x Pending See recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy

An affected version of the package is installed, but the impact of the vulnerability has not been assessed.
Avaya Aura® Session Manager 6.3.x, 7.0.x 6.3.21, 7.1.3 See PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.
Avaya Aura® System Manager 6.3.x, 7.0.x 7.1.3 For 7.x see PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.
For 6.3.x see recommended actions below.  This issue will be addressed in accordance with section five of Avaya's Product Security Vulnerability Response Policy
Avaya Aura® System Platform 6.4 through 6.4.1 6.4.2 If using an Avaya Common Server see PSN027066u
Avaya Aura® Utility Services 7.0.x 7.1.3 See PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.

Recommended Actions for System Products:
Avaya strongly recommends following networking and security best practices by implementing firewalls, ACLs, physical security or other appropriate access restrictions. Though Avaya believes such restrictions should always be in place, risk to Avaya products and the surrounding network from this potential vulnerability may be mitigated by ensuring these practices are implemented until such time as an Avaya provided product update or the recommended Avaya action is applied. Further restrictions as deemed necessary based on the customer's security policies may be required during this interim period, but the System Product operating system or application should not be modified unless the change is approved by Avaya. Making changes that are not approved may void the Avaya product service contract.

CVSS 3.0 Scoring and Metrics:

Avaya uses the Common Vulnerability Scoring System version 3 (CVSSv3) base score and metrics as reported by the vendor for the affected component(s) or by the National Institute of Standards and Technology in the National Vulnerability Database. In some cases, such as where CVSS information is not available from the vendor or NIST, Avaya will calculate the CVSSv3 base score and metrics. Customers are encouraged to calculate the Temporal and Environmental CVSSv3 scores to determine how the vulnerability could affect their specific implementation or environment. For more information on CVSS and how the score is calculated, see Common Vulnerability Scoring System v3.0: Specification Document.

Vulnerability CVSSv3 Base Score CVSSv3 Metrics
CVE-2017-5715
5.6 (Medium) CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVE-2017-5753
5.5 (Medium) CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVE-2017-5754
5.5 (Medium) CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

3. Avaya Software-Only Products:

Avaya software-only products operate on general-purpose operating systems. Occasionally vulnerabilities may be discovered in the underlying operating system or applications that come with the operating system. These vulnerabilities often do not impact the software-only product directly but may threaten the integrity of the underlying platform.

Product: Actions:
Avaya Aura® Application Enablement Services Upgrade to 7.1.3 or later. See PSN020346u for details on the remediaton and installation instructions for Avaya Aura® products.
Avaya Aura® Experience Portal Avaya is investigating vendor provided patches as they become available. This advisory will be updated when they are approved for installation.

Recommended Actions for Software-Only Products:
In the event that the affected package is installed, Avaya recommends following recommended actions supplied by Red Hat regarding their Enterprise Linux.

4. Additional Information:

Additional information may also be available via the Avaya support website and through your Avaya account representative. Please contact your Avaya product support representative, or dial 1-800-242-2121, with any questions.

5. Disclaimer:

ALL INFORMATION IS BELIEVED TO BE CORRECT AT THE TIME OF PUBLICATION, IS PROVIDED "AS IS", AND IS APPLICABLE ONLY TO PRODUCT VERSIONS ELIGIBLE FOR MANUFACTURER SUPPORT IN ACCORDANCE WITH AVAYA PRODUCT LIFE CYCLE POLICY. AVAYA INC., ON BEHALF ITSELF AND ITS SUBSIDIARIES AND AFFILIATES (HEREINAFTER COLLECTIVELY REFERRED TO AS "AVAYA"), DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND FURTHERMORE, AVAYA MAKES NO REPRESENTATIONS OR WARRANTIES THAT THE STEPS RECOMMENDED WILL ELIMINATE SECURITY OR VIRUS THREATS TO CUSTOMERS' SYSTEMS. IN NO EVENT SHALL AVAYA BE LIABLE FOR ANY DAMAGES WHATSOEVER ARISING OUT OF OR IN CONNECTION WITH THE INFORMATION OR RECOMMENDED ACTIONS PROVIDED HEREIN, INCLUDING DIRECT, INDIRECT, INCIDENTAL, STATUTORY, CONSEQUENTIAL DAMAGES, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF AVAYA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

THE INFORMATION PROVIDED HERE DOES NOT AFFECT THE SUPPORT AGREEMENTS IN PLACE FOR AVAYA PRODUCTS. SUPPORT FOR AVAYA PRODUCTS CONTINUES TO BE EXECUTED AS PER EXISTING AGREEMENTS WITH AVAYA.

6. Revision History:

V 1.0 - January 5, 2018 - Initial Statement issued.
V 2.0 - February 13, 2018 - Updated Description and Actions in Section 3. Updated Overall Severity Classification and CVSS scores to reflect Red Hat's updated scoring.
V 3.0 - June 14, 2018 - Updated affected versions and Information for AES, Breeze, CMS, CM, EP, One-X CES, SM, SMGR, and US. Updated Actions for AES.

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Independent security researchers can contact Avaya at securityalerts@avaya.com.

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