Amazon Linux 2 : libvncserver (ALAS-2018-1012)

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2018-1012.
#

include("compat.inc");

if (description)
{
  script_id(109691);
  script_version("1.1");
  script_cvs_date("Date: 2018/05/11 12:23:24");

  script_cve_id("CVE-2018-7225");
  script_xref(name:"ALAS", value:"2018-1012");

  script_name(english:"Amazon Linux 2 : libvncserver (ALAS-2018-1012)");
  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:
"Improper input sanitization in rfbProcessClientNormalMessage in
rfbserver.c

An issue was discovered in LibVNCServer through 0.9.11.
rfbProcessClientNormalMessage() in rfbserver.c does not sanitize
msg.cct.length, leading to access to uninitialized and potentially
sensitive data or possibly unspecified other impact (e.g., an integer
overflow) via specially crafted VNC packets.(CVE-2018-7225)"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://alas.aws.amazon.com/AL2/ALAS-2018-1012.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Run 'yum update libvncserver' to update your system."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libvncserver");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libvncserver-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:libvncserver-devel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");

  script_set_attribute(attribute:"patch_publication_date", value:"2018/05/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/05/11");
  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 != "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", cpu:"x86_64", reference:"libvncserver-0.9.9-12.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"libvncserver-debuginfo-0.9.9-12.amzn2")) flag++;
if (rpm_check(release:"AL2", cpu:"x86_64", reference:"libvncserver-devel-0.9.9-12.amzn2")) 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, "libvncserver / libvncserver-debuginfo / libvncserver-devel");
}