RHEL 6 : tigervnc (Unpatched Vulnerability)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory tigervnc. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(196470);
  script_version("1.0");
  script_set_attribute(attribute:"plugin_modification_date", value:"2024/05/11");

  script_cve_id(
    "CVE-2017-7392",
    "CVE-2017-7396",
    "CVE-2019-15691",
    "CVE-2019-15692",
    "CVE-2019-15693",
    "CVE-2019-15694",
    "CVE-2019-15695",
    "CVE-2020-26117"
  );

  script_name(english:"RHEL 6 : tigervnc (Unpatched Vulnerability)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat 6 host is affected by multiple vulnerabilities that will not be patched.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 6 host has one or more packages installed that are affected by multiple
vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - tigervnc: Stack buffer overflow in CMsgReader::readSetCursor (CVE-2019-15695)

  - tigervnc: certificate exceptions stored as authorities (CVE-2020-26117)

  - In TigerVNC 1.7.1 (SSecurityVeNCrypt.cxx SSecurityVeNCrypt::SSecurityVeNCrypt), an unauthenticated client
    can cause a small memory leak in the server. (CVE-2017-7392)

  - In TigerVNC 1.7.1 (CConnection.cxx CConnection::CConnection), an unauthenticated client can cause a small
    memory leak in the server. (CVE-2017-7396)

  - TigerVNC version prior to 1.10.1 is vulnerable to stack use-after-return, which occurs due to incorrect
    usage of stack memory in ZRLEDecoder. If decoding routine would throw an exception, ZRLEDecoder may try to
    access stack variable, which has been already freed during the process of stack unwinding. Exploitation of
    this vulnerability could potentially result into remote code execution. This attack appear to be
    exploitable via network connectivity. (CVE-2019-15691)

  - TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow. Vulnerability could be triggered
    from CopyRectDecoder due to incorrect value checks. Exploitation of this vulnerability could potentially
    result into remote code execution. This attack appear to be exploitable via network connectivity.
    (CVE-2019-15692)

  - TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which occurs in
    TightDecoder::FilterGradient. Exploitation of this vulnerability could potentially result into remote code
    execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15693)

  - TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which could be triggered from
    DecodeManager::decodeRect. Vulnerability occurs due to the signdness error in processing MemOutStream.
    Exploitation of this vulnerability could potentially result into remote code execution. This attack appear
    to be exploitable via network connectivity. (CVE-2019-15694)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package
is installed.");
  script_set_attribute(attribute:"solution", value:
"The vendor has acknowledged the vulnerabilities but no solution has been provided. Refer to the vendor for remediation
guidance.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-15695");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2020-26117");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/03/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2024/05/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:6");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:tigervnc");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Red Hat Local Security Checks");

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

  script_dependencies("ssh_get_info.nasl", "redhat_repos.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm.inc');
include('rhel.inc');

if (!get_kb_item("global_settings/vendor_unpatched"))
exit(0, "Unpatched Vulnerabilities Detection not active.");

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Red Hat' >!< os_release) audit(AUDIT_OS_NOT, 'Red Hat');
var os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
os_ver = os_ver[1];
if (!rhel_check_release(operator: 'ge', os_version: os_ver, rhel_version: '6')) audit(AUDIT_OS_NOT, 'Red Hat 6.x', 'Red Hat ' + os_ver);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'pkgs': [
      {'reference':'tigervnc', 'release':'6', 'rpm_spec_vers_cmp':TRUE, 'unpatched_pkg':'tigervnc'}
    ]
  }
];


var flag = 0;
foreach var constraint_array ( constraints ) {
  var repo_relative_urls = NULL;
  var enterprise_linux_flag = rhel_repo_urls_has_content_dist_rhel(repo_urls:repo_relative_urls);
  foreach var pkg ( constraint_array['pkgs'] ) {
    var unpatched_pkg = NULL;
    var _release = NULL;
    var sp = NULL;
    var el_string = NULL;
    var rpm_spec_vers_cmp = NULL;
    var exists_check = NULL;
    var cves = NULL;
    if (!empty_or_null(pkg['unpatched_pkg'])) unpatched_pkg = pkg['unpatched_pkg'];
    if (!empty_or_null(pkg['release'])) _release = 'RHEL' + pkg['release'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (unpatched_pkg &&
        _release &&
        (!exists_check || rpm_exists(release:_release, rpm:exists_check)) &&
        unpatched_package_exists(release:_release, package:unpatched_pkg, cves: cves)) flag++;
  }
}

if (flag)
{
  var extra = NULL;
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : unpatched_packages_report()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'tigervnc');
}