Security Advisory

On January 3, 2018, researchers disclosed security vulnerabilities known commonly in the industry as Spectre ^[4] and Meltdown ^[5]. On May 22, 2018, two variants of the Spectre vulnerability were disclosed ^[6] in the industry. Subsequently, other variants have been disclosed. Collectively, these vulnerabilities have been assigned the following CVEs:

These vulnerabilities take advantage of implementations for the speculative execution of instructions on most (if not all) modern processors and Operating Systems (OSs), including those supported by A10 products. They could allow an unprivileged attacker, in specific circumstances, to read privileged memory belonging to other processes or memory allocated to the Operating System (OS) kernel. To successfully exploit these weaknesses and gain access to restricted memory, an attack requires the execution of crafted, custom code on the target device or system.

ACOS products that support the External Health Monitor feature are potentially exposed to misuse of the feature by malicious, Read-Write privileged administrators. Accordingly, A10 recommends limiting access to such critical infrastructure networking equipment to only trusted administrators from trusted administrative networks and hosts as a defense against active exploit of these vulnerabilities and to ensure that only code fully-trusted by the customer is deployed to these products.

A10 products and release families that support this ACOS feature and warrant these administrative considerations include:

A10 aGalaxy and other ACOS products do not support this feature and are accordingly unaffected by these vulnerabilities. These products include:

For all virtualized A10 products, including ACOS vThunder, A10 recommends that customers ensure that their Host-OSs (hypervisors) are updated as necessary to address these vulnerabilities and that their underlying platforms have corresponding, appropriate firmware updates.

In addition, for A10 Lightning ADC and Harmony Controller virtualized products, root-level access to the Local OS shell and Container Management System (CMS) software is available to product administrators. A10 recommends that only trusted administrators likewise be allowed access to these root-level, privileged services to ensure that malicious code which could exploit these vulnerabilities does not enter or become established in virtual instances of these products.

For A10 Harmony Controller Appliance and Hybrid Virtual Appliance products, root-level access to the Host OS shell is also available to product administrators. A10 additionally recommends that only trusted administrators likewise be allowed access to this service to ensure that potentially malicious code from untrusted parties does not become instantiated in these appliances.

To improve the ability of customers to manage ACOS devices, in light of these issues and others like them in the future, A10 will harden and enhance ACOS configuration and management capabilities for this feature as described in the Affected Releases section below.

A10 continues to investigate the Spectre and Meltdown vulnerabilities for further potential impacts and will update this advisory as additional information becomes available. As this investigation proceeds, A10 PSIRT looks forward to feedback and questions on these issues. Customers and partners are welcome to contact the A10 Technical Assistance Center (TAC) or their A10 Sales Representatives. Others are invited to contact A10 PSIRT via email.

General, recommended practices for the administration of A10 products are described in the Summary section above regarding these potential exposures. Other specific workarounds or mitigations are described below.

RESTRICTING EXTENDED HEALTH MONITOR ACCESS

For A10 products with an ACOS 4.1.x release and which are using local database authentication for administration, a workaround is available to restrict administrators’ use of the External Health Monitor feature.

For such configurations, include the following Role-Based Access (RBA) configuration constraint for all ACOS administrators except those sufficiently trusted to ensure that the ACOS system is not exposed to potentially malicious code, either by their malicious use or by compromise of their administrative systems.

1. Enable RBA (if not already enabled)

2. Apply the constraint for all system-wide (shared partition) administrative users. The CLI example below uses adminuser1 for the username of the account.

3. Apply the constraint for all Application Delivery Partition (ADP) administrative users. The CLI example below uses adminuser5 and partition-5 for the username and partition of the account; respectively.

4. If the External Health Monitor feature is not used in the A10 product’s deployment scope, stop here.

5. If the administration policy of the A10 product is to only trust the ACOS default (root) administrator account (username admin) in this regard, stop here.

6. Otherwise, remove the constraint for the select administrative user(s) sufficiently trusted for this administrative capability. The CLI example below uses adminuser3 for the username of the account.

For partition constrained administrative users:

REVIEWING EXTENDED HEALTH MONITOR CONFIGURATION

External health monitor scripts should be reviewed and audited to ensure their integrity and intended use in the ACOS system. Instantiated scripts can be listed by the show health external ACOS CLI command and inspected individually using the show health external file.ext ACOS CLI command, where file.ext is the of the indicated script files listed.

MONITORING EXTENDED HEALTH MONITOR ACTIVITY

External health monitor activity can be monitored via the ACOS Audit Log. This log can be configured to log events to an external server through the logging auditlog host CLI command. Import operations can be detected on the logging server by filtering for the following strings and reporting match events for administrative review.

• For ACOS 4.x Systems: import health-external
• For ACOS 2.x Systems: health external import

Software updates that address these vulnerabilities are or will be published at the following URL:
https://www.a10networks.com/support/axseries/software-downloads

The following table shares brief descriptions for the vulnerabilities addressed in this document.

None.

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This document is provided on an "AS IS" basis and does not imply any kind of guarantee or warranty, including the warranties of merchantability, non-infringement or fitness for a particular use. Your use of the information in this document or materials linked from this document is at your own risk. A10 Networks, Inc. reserves the right to change or update the information in this document at any time.