Amazon Linux AMI : kernel (ALAS-2017-845) (Stack Clash)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2017-845.
#

include("compat.inc");

if (description)
{
  script_id(100874);
  script_version("3.9");
  script_cvs_date("Date: 2019/04/10 16:10:16");

  script_cve_id("CVE-2017-1000364", "CVE-2017-1000371");
  script_xref(name:"ALAS", value:"2017-845");

  script_name(english:"Amazon Linux AMI : kernel (ALAS-2017-845) (Stack Clash)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Amazon Linux AMI host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"An issue was discovered in the size of the stack guard page on Linux,
specifically a 4k stack guard page is not sufficiently large and can
be jmp'ed over, this affects Linux Kernel versions 4.11.5 and earlier
(the stackguard page was introduced in 2010). (CVE-2017-1000364)

The offset2lib patch as used by the Linux Kernel contains a
vulnerability, if RLIMIT_STACK is set to RLIMIT_INFINITY and 1
Gigabyte of memory is allocated (the maximum under the 1/4
restriction) then the stack will be grown down to 0x80000000, and as
the PIE binary is mapped above 0x80000000 the minimum distance between
the end of the PIE binary's read-write segment and the start of the
stack becomes small enough that the stack guard page can be jumped
over by an attacker. This is a different issue than CVE-2017-1000370
and CVE-2017-1000365 . (CVE-2017-1000371)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/ALAS-2017-845.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update kernel' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/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:"metasploit_name", value:'rsh_stack_clash_priv_esc.rb');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-i686");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-headers");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:kernel-tools-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/06/19");
  script_set_attribute(attribute:"in_the_news", value:"true");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/06/20");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Amazon Linux Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

release = get_kb_item("Host/AmazonLinux/release");
if (isnull(release) || !strlen(release)) audit(AUDIT_OS_NOT, "Amazon Linux");
os_ver = pregmatch(pattern: "^AL(A|\d)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "A")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux AMI", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (rpm_check(release:"ALA", reference:"kernel-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-debuginfo-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"i686", reference:"kernel-debuginfo-common-i686-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-devel-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-doc-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-headers-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-debuginfo-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-devel-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-4.9.27-14.33.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-debuginfo-4.9.27-14.33.amzn1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:rpm_report_get());
  else security_hole(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "kernel / kernel-debuginfo / kernel-debuginfo-common-i686 / etc");
}