Vulnerabilities > CVE-2018-7226 - Integer Overflow or Wraparound vulnerability in Vncterm Project Vncterm 0.1/0.9.10

047910
CVSS 9.8 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
vncterm-project
CWE-190
critical
nessus
NVD
Published: 2018-02-19
Updated: 2024-11-21

Summary

An issue was discovered in vcSetXCutTextProc() in VNConsole.c in LinuxVNC and VNCommand from the LibVNC/vncterm distribution through 0.9.10. Missing sanitization of the client-specified message length may cause integer overflow or possibly have unspecified other impact via a specially crafted VNC packet.

Vulnerable Configurations

Part Description Count
Application
Vncterm_Project
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Forced Integer Overflow
    This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.

Nessus

NASL familyGentoo Local Security Checks
NASL idGENTOO_GLSA-201908-05.NASL
descriptionThe remote host is affected by the vulnerability described in GLSA-201908-05 (LibVNCServer: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in LibVNCServer. Please review the CVE identifiers referenced below for details. Impact : Please review the referenced CVE identifiers for details. Workaround : There is no known workaround at this time.
last seen2020-06-01
modified2020-06-02
plugin id127563
published2019-08-12
reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/127563
titleGLSA-201908-05 : LibVNCServer: Multiple vulnerabilities
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Gentoo Linux Security Advisory GLSA 201908-05.
#
# The advisory text is Copyright (C) 2001-2020 Gentoo Foundation, Inc.
# and licensed under the Creative Commons - Attribution / Share Alike 
# license. See http://creativecommons.org/licenses/by-sa/3.0/
#

include("compat.inc");

if (description)
{
  script_id(127563);
  script_version("1.2");
  script_cvs_date("Date: 2020/01/06");

  script_cve_id("CVE-2018-20019", "CVE-2018-20020", "CVE-2018-20021", "CVE-2018-20022", "CVE-2018-20023", "CVE-2018-20024", "CVE-2018-7225", "CVE-2018-7226");
  script_xref(name:"GLSA", value:"201908-05");

  script_name(english:"GLSA-201908-05 : LibVNCServer: Multiple vulnerabilities");
  script_summary(english:"Checks for updated package(s) in /var/db/pkg");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Gentoo host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The remote host is affected by the vulnerability described in GLSA-201908-05
(LibVNCServer: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in LibVNCServer. Please
      review the CVE identifiers referenced below for details.
  
Impact :

    Please review the referenced CVE identifiers for details.
  
Workaround :

    There is no known workaround at this time."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security.gentoo.org/glsa/201908-05"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"All LibVNCServer users should upgrade to the latest version:
      # emerge --sync
      # emerge --ask --oneshot --verbose '>=net-libs/libvncserver-0.9.12'"
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  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_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-7226");
  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:gentoo:linux:libvncserver");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:gentoo:linux");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/02/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/08/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/08/12");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Gentoo Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Gentoo/release", "Host/Gentoo/qpkg-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("qpkg.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Gentoo/release")) audit(AUDIT_OS_NOT, "Gentoo");
if (!get_kb_item("Host/Gentoo/qpkg-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (qpkg_check(package:"net-libs/libvncserver", unaffected:make_list("ge 0.9.12"), vulnerable:make_list("lt 0.9.12"))) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:qpkg_report_get());
  else security_hole(0);
  exit(0);
}
else
{
  tested = qpkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "LibVNCServer");
}

References