Severity

High

Vendor

Canonical Ubuntu

Versions Affected

• Canonical Ubuntu 16.04

Description

USN-3777-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu 16.04 LTS.

Jann Horn discovered that the vmacache subsystem did not properly handle sequence number overflows, leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2018-17182)

It was discovered that the paravirtualization implementation in the Linux kernel did not properly handle some indirect calls, reducing the effectiveness of Spectre v2 mitigations for paravirtual guests. A local attacker could use this to expose sensitive information. (CVE-2018-15594)

It was discovered that microprocessors utilizing speculative execution and prediction of return addresses via Return Stack Buffer (RSB) may allow unauthorized memory reads via sidechannel attacks. An attacker could use this to expose sensitive information. (CVE-2018-15572)

Andy Lutomirski and Mika Penttilä discovered that the KVM implementation in the Linux kernel did not properly check privilege levels when emulating some instructions. An unprivileged attacker in a guest VM could use this to escalate privileges within the guest. (CVE-2018-10853)

It was discovered that a stack-based buffer overflow existed in the iSCSI target implementation of the Linux kernel. A remote attacker could use this to cause a denial of service (system crash). (CVE-2018-14633)

It was discovered that a memory leak existed in the IRDA subsystem of the Linux kernel. A local attacker could use this to cause a denial of service (kernel memory exhaustion). (CVE-2018-6554)

It was discovered that a use-after-free vulnerability existed in the IRDA implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2018-6555)

CVEs contained in this USN include: CVE-2018-10853, CVE-2018-14633, CVE-2018-15572, CVE-2018-15594, CVE-2018-17182, CVE-2018-6554, CVE-2018-6555

Affected Cloud Foundry Products and Versions

Severity is high unless otherwise noted.

• Cloud Foundry BOSH xenial-stemcells are vulnerable, including:
  • 97.x versions prior to 97.19
  • All other stemcells not listed.

Mitigation

Users of affected products are strongly encouraged to follow one of the mitigations below:

• The Cloud Foundry project recommends upgrading the following BOSH xenial-stemcells:
  • Upgrade 97.x versions to 97.19
  • All other stemcells should be upgraded to the latest version available on bosh.io.

References

• USN-3777-2
• CVE-2018-10853
• CVE-2018-14633
• CVE-2018-15572
• CVE-2018-15594
• CVE-2018-17182
• CVE-2018-6554
• CVE-2018-6555