Vulnerabilities > CVE-2020-3941 - Race Condition vulnerability in VMWare Tools

047910
CVSS 4.4 - MEDIUM
Attack vector
LOCAL
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
local
vmware
CWE-362
nessus
NVD
Published: 2020-01-15
Updated: 2020-02-05

Summary

The repair operation of VMware Tools for Windows 10.x.y has a race condition which may allow for privilege escalation in the Virtual Machine where Tools is installed. This vulnerability is not present in VMware Tools 11.x.y since the affected functionality is not present in VMware Tools 11.

Vulnerable Configurations

Part Description Count
Application
Vmware
21
OS
Microsoft
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Leveraging Race Conditions
    This attack targets a race condition occurring when multiple processes access and manipulate the same resource concurrently and the outcome of the execution depends on the particular order in which the access takes place. The attacker can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance a race condition can occur while accessing a file, the attacker can trick the system by replacing the original file with his version and cause the system to read the malicious file.
  • Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
    This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. The typical example is the file access. The attacker can leverage a file access race condition by "running the race", meaning that he would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the attacker could do something such as replace the file and cause an escalation of privilege.

Nessus

NASL familyWindows
NASL idVMWARE_TOOLS_WIN_VMSA_2020_0002.NASL
descriptionThe version of VMware Tools installed on the remote Windows host is 10.x, which is prior to 11.0.0. It is, therefore, affected by a race condition which may allow for privilege escalation in the virtual machine where Tools is installed. An authenticated, local attacker can exploit this to escalate their privileges on a Windows virtual machine. Note that Nessus has not tested for these issues but has instead relied only on the application
last seen2020-05-23
modified2020-01-23
plugin id133208
published2020-01-23
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/133208
titleVMware Tools 10.x < 11.0.0 Privilege Escalation (VMSA-2020-0002)
code
#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(133208);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/22");

  script_cve_id("CVE-2020-3941");
  script_xref(name:"VMSA", value:"2020-0002");
  script_xref(name:"IAVB", value:"2020-B-0005");

  script_name(english:"VMware Tools 10.x < 11.0.0 Privilege Escalation (VMSA-2020-0002)");

  script_set_attribute(attribute:"synopsis", value:
"A virtualization tool suite is installed on the remote Windows host is affected by a privilege escalation
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of VMware Tools installed on the remote Windows host is 10.x, which is prior to 11.0.0. It is, therefore,
affected by a race condition which may allow for privilege escalation in the virtual machine where Tools is installed.
An authenticated, local attacker can exploit this to escalate their privileges on a Windows virtual machine.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://www.vmware.com/security/advisories/VMSA-2020-0002.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade to VMware Tools version 11.0.0 or later or apply the workaround mentioned in the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:M/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:L/AC:H/PR:L/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-2020-3941");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/01/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/01/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:vmware:vmware_tools");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Windows");

  script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("vmware_tools_installed.nbin", "vmware_vsphere_detect.nbin", "vmware_esxi_detection.nbin");
  script_require_keys("SMB/Registry/Enumerated", "installed_sw/VMware Tools", "Host/ESXi/checked", "Settings/ParanoidReport");

  exit(0);
}

include('vcf.inc');

get_kb_item_or_exit("SMB/Registry/Enumerated");

# Paranoid due to lack of workaround check
if (report_paranoia < 2)
  audit(AUDIT_PARANOID);

app_info = vcf::get_app_info(app:'VMware Tools', win_local:TRUE);
constraints = [{ 'min_version' : '10.0', 'fixed_version' : '11.0.0' }];
vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);

References