Amazon Linux AMI : kernel (ALAS-2018-1049)

2018-08-07T00:00:00
ID ALA_ALAS-2018-1049.NASL
Type nessus
Reporter This script is Copyright (C) 2018 and is owned by Tenable, Inc. or an Affiliate thereof.
Modified 2020-03-02T00:00:00

Description

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service. An attacker can induce a denial of service condition by sending specially modified packets within ongoing TCP sessions. Maintaining the denial of service condition requires continuous two-way TCP sessions to a reachable open port. Thus, the attacks cannot be performed using spoofed IP addresses. ( https://www.kb.cert.org/vuls/id/962459 )

                                        
                                            #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2018-1049.
#

include("compat.inc");

if (description)
{
  script_id(111553);
  script_version("1.3");
  script_cvs_date("Date: 2018/12/18 10:18:58");

  script_cve_id("CVE-2018-5390");
  script_xref(name:"ALAS", value:"2018-1049");

  script_name(english:"Amazon Linux AMI : kernel (ALAS-2018-1049)");
  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:
"Linux kernel versions 4.9+ can be forced to make very expensive calls
to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every
incoming packet which can lead to a denial of service. An attacker can
induce a denial of service condition by sending specially modified
packets within ongoing TCP sessions. Maintaining the denial of service
condition requires continuous two-way TCP sessions to a reachable open
port. Thus, the attacks cannot be performed using spoofed IP
addresses. ( https://www.kb.cert.org/vuls/id/962459 )"
  );
  # https://www.kb.cert.org/vuls/id/962459
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.kb.cert.org/vuls/id/962459/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/ALAS-2018-1049.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Run 'yum update kernel' and reboot your instance to update your
system."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");

  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-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:"2018/08/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/08/07");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018 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-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-debuginfo-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"i686", reference:"kernel-debuginfo-common-i686-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-devel-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-headers-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-debuginfo-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-devel-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-4.14.59-64.43.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-debuginfo-4.14.59-64.43.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");
}