Amazon Linux 2 : gnutls (ALAS-2018-1120)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2018-1120.
#

include("compat.inc");

if (description)
{
  script_id(119503);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/18");

  script_cve_id("CVE-2018-10844", "CVE-2018-10845", "CVE-2018-10846");
  script_xref(name:"ALAS", value:"2018-1120");

  script_name(english:"Amazon Linux 2 : gnutls (ALAS-2018-1120)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Amazon Linux 2 host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"It was found that GnuTLS's implementation of HMAC-SHA-256 was
vulnerable to Lucky Thirteen-style attack. A remote attacker could use
this flaw to conduct distinguishing attacks and plain text recovery
attacks via statistical analysis of timing data using crafted
packets.(CVE-2018-10844)

It was found that GnuTLS's implementation of HMAC-SHA-384 was
vulnerable to a Lucky Thirteen-style attack. A remote attacker could
use this flaw to conduct distinguishing attacks and plain text
recovery attacks via statistical analysis of timing data using crafted
packets.(CVE-2018-10845)

A cache-based side channel attack was found in the way GnuTLS
implements CBC-mode cipher suites. An attacker could use a combination
of 'Just in Time' Prime+probe and Lucky-13 attacks to recover plain
text in a cross-VM attack scenario.(CVE-2018-10846)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/AL2/ALAS-2018-1120.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update gnutls' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls-c++");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls-dane");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gnutls-utils");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/08/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/12/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/12/10");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018-2020 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 != "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);


flag = 0;
if (rpm_check(release:"AL2", reference:"gnutls-3.3.29-8.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"gnutls-c++-3.3.29-8.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"gnutls-dane-3.3.29-8.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"gnutls-debuginfo-3.3.29-8.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"gnutls-devel-3.3.29-8.amzn2")) flag++;
if (rpm_check(release:"AL2", reference:"gnutls-utils-3.3.29-8.amzn2")) 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, "gnutls / gnutls-c++ / gnutls-dane / gnutls-debuginfo / gnutls-devel / etc");
}