The remote Redhat Enterprise Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2018:0020 advisory.

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

    Security Fix(es):

    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. (CVE-2017-5753, Important)

    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. (CVE-2017-5715, Important)

    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. (CVE-2017-5754, Important)

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

    Red Hat would like to thank Google Project Zero for reporting these issues.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

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RHEL 6 : kernel (RHSA-2018:0020)

medium Nessus Plugin ID 105562

Version 3.21