PSIRT Advisory

Meltdown and Spectre class vulnerabilities

Summary

A new type of side channel attacks impact most processors including Intel, AMD, ARM, etc. These attacks allow malicious userspace processes to read kernel memory, thus potentially causing kernel sensitive information to leak.

These attacks are referred to as Meltdown and Spectre class vulnerabilities, and variants of them:

o CVE-2017-5753 Variant 1, Bounds Check Bypass (Spectre)
o CVE-2017-5715 Variant 2, Branch Target Injection (Spectre)
o CVE-2017-5754 Variant 3, Rogue Data Cache Load (Meltdown)
o CVE-2018-3640 Variant 3a, Rogue System Register Read (RSRE)
o CVE-2018-3639 Variant 4: Speculative Store Bypass (SSB)
o No CVE assigned: Eight additional Spectre-class flaws (Spectre-NG)

Impact

Information Disclosure, Privilege Escalation

Affected Products

The following products run processors that may be affected by Meltdown/Spectre and variants; they are not, however, directly exploitable:

FortiOS
FortiAP
FortiSwitch
FortiAnalyzer

Indeed Fortinet products are designed to not permit arbitrary code execution in the user space under regular conditions. Thus Meltdown/Spectre attacks and their variants are only possible if the attack is combined with an additional local or remote code execution vulnerability, unrelated to these two issues - Meltdown and Spectre can then aggravate the situation, if such vulnerabilities exist and are successfully exploited.

Solutions

To lower your attack risk to Meltdown/Spectre and reduce the possibility of an "already existing local or remote code execution vulnerability", upgrading to our latest publicly available software version is highly recommended.

At the moment, Fortinet is still evaluating an OS kernel patch plan. Due to the fact the OS kernel patch, by nature, slows the performance down, and considering the low risk, OS kernel patches may be produced and update details, if have any, will be given in product release notes.

Please note that in any case, any vulnerability (Local code execution or remote code execution) that would enable the exploitability of Spectre/Meltdown class vulnerabilities will always be treated as a high/critical severity vulnerability, and swiftly fixed.

Update History

01-04-2018 Initial version.
01-18-2018 Final assessment.
05-22-2018 Remove other vendors (Microsoft Windows/VMware) patch info.
05-22-2018 Include variant v3a, v4 and Spectre-ng vulnerabilities.