Amazon Linux 2 : kernel (ALAS-2020-1440)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2020-1440.
#

include('compat.inc');

if (description)
{
  script_id(137571);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/03/06");

  script_cve_id("CVE-2020-12657", "CVE-2020-12826");
  script_xref(name:"ALAS", value:"2020-1440");

  script_name(english:"Amazon Linux 2 : kernel (ALAS-2020-1440)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"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)

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)");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/AL2/ALAS-2020-1440.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:"2020/06/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/06/18");

  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-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-livepatch-4.14.177-139.253");
  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:"p-cpe:/a:amazon:linux:python-perf");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:python-perf-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  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", "linux_alt_patch_detect.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");
include("hotfixes.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 != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

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

if (get_one_kb_item("Host/kpatch/kernel-cves"))
{
  set_hotfix_type("kpatch");
  cve_list = make_list("CVE-2020-12657", "CVE-2020-12826");
  if (hotfix_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, "kpatch hotfix for ALAS-2020-1440");
  }
  else
  {
    __rpm_report = hotfix_reporting_text();
  }
}

flag = 0;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-debuginfo-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-debuginfo-common-x86_64-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-devel-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"kernel-headers-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-livepatch-4.14.177-139.253-1.0-0.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-tools-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-tools-debuginfo-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"kernel-tools-devel-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"perf-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"perf-debuginfo-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"python-perf-4.14.177-139.253.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"python-perf-debuginfo-4.14.177-139.253.amzn2")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  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-x86_64 / etc");
}