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Ubuntu: (Multiple Advisories) (CVE-2018-18955): Linux kernel (HWE) vulnerabilities

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Ubuntu: (Multiple Advisories) (CVE-2018-18955): Linux kernel (HWE) vulnerabilities

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
11/16/2018
Created
03/19/2019
Added
12/07/2018
Modified
08/25/2021

Description

In the Linux kernel 4.15.x through 4.19.x before 4.19.2, map_write() in kernel/user_namespace.c allows privilege escalation because it mishandles nested user namespaces with more than 5 UID or GID ranges. A user who has CAP_SYS_ADMIN in an affected user namespace can bypass access controls on resources outside the namespace, as demonstrated by reading /etc/shadow. This occurs because an ID transformation takes place properly for the namespaced-to-kernel direction but not for the kernel-to-namespaced direction.

Solution(s)

  • ubuntu-upgrade-linux-image-4-15-0-1025-gcp
  • ubuntu-upgrade-linux-image-4-15-0-1027-kvm
  • ubuntu-upgrade-linux-image-4-15-0-1029-aws
  • ubuntu-upgrade-linux-image-4-15-0-1029-raspi2
  • ubuntu-upgrade-linux-image-4-15-0-42-generic
  • ubuntu-upgrade-linux-image-4-15-0-42-generic-lpae
  • ubuntu-upgrade-linux-image-4-15-0-42-lowlatency
  • ubuntu-upgrade-linux-image-4-15-0-42-snapdragon
  • ubuntu-upgrade-linux-image-4-18-0-1004-gcp
  • ubuntu-upgrade-linux-image-4-18-0-1005-kvm
  • ubuntu-upgrade-linux-image-4-18-0-1006-aws
  • ubuntu-upgrade-linux-image-4-18-0-1007-raspi2
  • ubuntu-upgrade-linux-image-4-18-0-12-generic
  • ubuntu-upgrade-linux-image-4-18-0-12-generic-lpae
  • ubuntu-upgrade-linux-image-4-18-0-12-lowlatency
  • ubuntu-upgrade-linux-image-4-18-0-12-snapdragon
  • ubuntu-upgrade-linux-image-aws
  • ubuntu-upgrade-linux-image-gcp
  • ubuntu-upgrade-linux-image-generic
  • ubuntu-upgrade-linux-image-generic-hwe-16-04
  • ubuntu-upgrade-linux-image-generic-lpae
  • ubuntu-upgrade-linux-image-generic-lpae-hwe-16-04
  • ubuntu-upgrade-linux-image-gke
  • ubuntu-upgrade-linux-image-kvm
  • ubuntu-upgrade-linux-image-lowlatency
  • ubuntu-upgrade-linux-image-lowlatency-hwe-16-04
  • ubuntu-upgrade-linux-image-oem
  • ubuntu-upgrade-linux-image-raspi2
  • ubuntu-upgrade-linux-image-snapdragon

References

  • USN-3832-1
  • USN-3833-1
  • USN-3835-1
  • USN-3836-1
  • USN-3836-2
  • CVE-2018-18955

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