Ubuntu 16.04 LTS : Linux kernel (HWE) regression (USN-3718-2)

2018-07-24T00:00:00
ID UBUNTU_USN-3718-2.NASL
Type nessus
Reporter Ubuntu Security Notice (C) 2018-2020 Canonical, Inc. / NASL script (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2018-07-24T00:00:00

Description

USN-3695-2 fixed vulnerabilities in the Linux Hardware Enablement Kernel (HWE) kernel for Ubuntu 16.04 LTS. Unfortunately, the fix for CVE-2018-1108 introduced a regression where insufficient early entropy prevented services from starting, leading in some situations to a failure to boot, This update addresses the issue.

We apologize for the inconvenience.

Jann Horn discovered that the Linux kernel's implementation of random seed data reported that it was in a ready state before it had gathered sufficient entropy. An attacker could use this to expose sensitive information. (CVE-2018-1108)

Wen Xu discovered that the ext4 file system implementation in the Linux kernel did not properly initialize the crc32c checksum driver. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1094)

It was discovered that the cdrom driver in the Linux kernel contained an incorrect bounds check. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-10940)

Wen Xu discovered that the ext4 file system implementation in the Linux kernel did not properly validate xattr sizes. A local attacker could use this to cause a denial of service (system crash). (CVE-2018-1095)

Jann Horn discovered that the 32 bit adjtimex() syscall implementation for 64 bit Linux kernels did not properly initialize memory returned to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-11508)

It was discovered that an information leak vulnerability existed in the floppy driver in the Linux kernel. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-7755).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3718-2. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(111267);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/09/17");

  script_cve_id("CVE-2018-1094", "CVE-2018-10940", "CVE-2018-1095", "CVE-2018-1108", "CVE-2018-11508", "CVE-2018-7755");
  script_xref(name:"USN", value:"3718-2");

  script_name(english:"Ubuntu 16.04 LTS : Linux kernel (HWE) regression (USN-3718-2)");
  script_summary(english:"Checks dpkg output for updated packages.");

  script_set_attribute(
    attribute:"synopsis",
    value:
"The remote Ubuntu host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description",
    value:
"USN-3695-2 fixed vulnerabilities in the Linux Hardware Enablement
Kernel (HWE) kernel for Ubuntu 16.04 LTS. Unfortunately, the fix for
CVE-2018-1108 introduced a regression where insufficient early entropy
prevented services from starting, leading in some situations to a
failure to boot, This update addresses the issue.

We apologize for the inconvenience.

Jann Horn discovered that the Linux kernel's implementation of random
seed data reported that it was in a ready state before it had gathered
sufficient entropy. An attacker could use this to expose sensitive
information. (CVE-2018-1108)

Wen Xu discovered that the ext4 file system implementation in the
Linux kernel did not properly initialize the crc32c checksum driver. A
local attacker could use this to cause a denial of service (system
crash). (CVE-2018-1094)

It was discovered that the cdrom driver in the Linux kernel contained
an incorrect bounds check. A local attacker could use this to expose
sensitive information (kernel memory). (CVE-2018-10940)

Wen Xu discovered that the ext4 file system implementation in the
Linux kernel did not properly validate xattr sizes. A local attacker
could use this to cause a denial of service (system crash).
(CVE-2018-1095)

Jann Horn discovered that the 32 bit adjtimex() syscall implementation
for 64 bit Linux kernels did not properly initialize memory returned
to user space in some situations. A local attacker could use this to
expose sensitive information (kernel memory). (CVE-2018-11508)

It was discovered that an information leak vulnerability existed in
the floppy driver in the Linux kernel. A local attacker could use this
to expose sensitive information (kernel memory). (CVE-2018-7755).

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://usn.ubuntu.com/3718-2/"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-azure");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-hwe-16.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-hwe-16.04");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-gke");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-hwe-16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/03/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/07/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/07/24");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2018-2020 Canonical, Inc. / NASL script (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl", "linux_alt_patch_detect.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("ksplice.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(16\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 16.04", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Ubuntu", cpu);

if (get_one_kb_item("Host/ksplice/kernel-cves"))
{
  rm_kb_item(name:"Host/uptrack-uname-r");
  cve_list = make_list("CVE-2018-1094", "CVE-2018-10940", "CVE-2018-1095", "CVE-2018-1108", "CVE-2018-11508", "CVE-2018-7755");
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, "KSplice hotfix for USN-3718-2");
  }
  else
  {
    _ubuntu_report = ksplice_reporting_text();
  }
}

flag = 0;

if (ubuntu_check(osver:"16.04", pkgname:"linux-image-4.15.0-1014-gcp", pkgver:"4.15.0-1014.14~16.04.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-4.15.0-1018-azure", pkgver:"4.15.0-1018.18~16.04.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-4.15.0-29-generic", pkgver:"4.15.0-29.31~16.04.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-4.15.0-29-generic-lpae", pkgver:"4.15.0-29.31~16.04.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-4.15.0-29-lowlatency", pkgver:"4.15.0-29.31~16.04.1")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-azure", pkgver:"4.15.0.1018.24")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-gcp", pkgver:"4.15.0.1014.26")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-generic-hwe-16.04", pkgver:"4.13.0.45.64")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-generic-lpae-hwe-16.04", pkgver:"4.13.0.45.64")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-gke", pkgver:"4.15.0.1014.26")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"linux-image-lowlatency-hwe-16.04", pkgver:"4.13.0.45.64")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "linux-image-4.15-azure / linux-image-4.15-gcp / etc");
}