Amazon Linux AMI : kernel (ALAS-2020-1382)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux AMI Security Advisory ALAS-2020-1382.
#

include('compat.inc');

if (description)
{
  script_id(138631);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/02/29");

  script_cve_id("CVE-2020-10711", "CVE-2020-12657", "CVE-2020-12826");
  script_xref(name:"ALAS", value:"2020-1382");

  script_name(english:"Amazon Linux AMI : kernel (ALAS-2020-1382)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux AMI host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"A NULL pointer dereference flaw was found in the Linux kernel's
SELinux subsystem in versions before 5.7. This flaw occurs while
importing the Commercial IP Security Option (CIPSO) protocol's
category bitmap into the SELinux extensible bitmap via the'
ebitmap_netlbl_import' routine. While processing the CIPSO restricted
bitmap tag in the 'cipso_v4_parsetag_rbm' routine, it sets the
security attribute to indicate that the category bitmap is present,
even if it has not been allocated. This issue leads to a NULL pointer
dereference issue while importing the same category bitmap into
SELinux. This flaw allows a remote network user to crash the system
kernel, resulting in a denial of service. (CVE-2020-10711)

An issue was discovered in the Linux kernel before 5.6.5. There is a
use-after-free in block/bfq-iosched.c related to
bfq_idle_slice_timer_body. (CVE-2020-12657)

A signal access-control issue was discovered in the Linux kernel
before 5.6.5, aka CID-7395ea4e65c2. Because exec_id in
include/linux/sched.h is only 32 bits, an integer overflow can
interfere with a do_notify_parent protection mechanism. A child
process can send an arbitrary signal to a parent process in a
different security domain. Exploitation limitations include the amount
of elapsed time before an integer overflow occurs, and the lack of
scenarios where signals to a parent process present a substantial
operational threat. (CVE-2020-12826)");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/ALAS-2020-1382.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:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-12657");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/05/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/07/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/07/20");

  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:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2020-2024 and is owned by Tenable, Inc. or an Affiliate thereof.");

  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-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-debuginfo-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"i686", reference:"kernel-debuginfo-common-i686-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-devel-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-headers-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-debuginfo-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"kernel-tools-devel-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-4.14.177-107.254.amzn1")) flag++;
if (rpm_check(release:"ALA", reference:"perf-debuginfo-4.14.177-107.254.amzn1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(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");
}