Vulnerabilities > CVE-2020-0789 - Link Following vulnerability in Microsoft Visual Studio 2019

047910
CVSS 7.1 - HIGH
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
LOW
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
HIGH
local
low complexity
microsoft
CWE-59
nessus

Summary

A denial of service vulnerability exists when the Visual Studio Extension Installer Service improperly handles hard links, aka 'Visual Studio Extension Installer Service Denial of Service Vulnerability'.

Vulnerable Configurations

Part Description Count
Application
Microsoft
41

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Symlink Attack
    An attacker positions a symbolic link in such a manner that the targeted user or application accesses the link's endpoint, assuming that it is accessing a file with the link's name. The endpoint file may be either output or input. If the file is output, the result is that the endpoint is modified, instead of a file at the intended location. Modifications to the endpoint file may include appending, overwriting, corrupting, changing permissions, or other modifications. In some variants of this attack the attacker may be able to control the change to a file while in other cases they cannot. The former is especially damaging since the attacker may be able to grant themselves increased privileges or insert false information, but the latter can also be damaging as it can expose sensitive information or corrupt or destroy vital system or application files. Alternatively, the endpoint file may serve as input to the targeted application. This can be used to feed malformed input into the target or to cause the target to process different information, possibly allowing the attacker to control the actions of the target or to cause the target to expose information to the attacker. Moreover, the actions taken on the endpoint file are undertaken with the permissions of the targeted user or application, which may exceed the permissions that the attacker would normally have.
  • Accessing, Modifying or Executing Executable Files
    An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
  • Leverage Executable Code in Non-Executable Files
    An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.

Nessus

NASL familyWindows : Microsoft Bulletins
NASL idSMB_NT_MS20_MAR_VISUAL_STUDIO.NASL
descriptionThe Microsoft Visual Studio Products are missing security updates. It is, therefore, affected by multiple vulnerabilities : - A spoofing vulnerability exists in Microsoft Visual Studio as it includes a reply URL that is not secured by SSL. An attacker who successfully exploited this vulnerability could compromise the access tokens, exposing security and privacy risks. (CVE-2020-0884) - An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector or the Visual Studio Standard Collector allows file creation in arbitrary locations. (CVE-2020-0810) - An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector Service improperly handles file operations. An attacker who successfully exploited this vulnerability could gain elevated privileges. An attacker with unprivileged access to a vulnerable system could exploit this vulnerability. The security update addresses the vulnerability by ensuring the Diagnostics Hub Standard Collector Service properly handles file operations. (CVE-2020-0793) - A denial of service vulnerability exists when the Visual Studio Extension Installer Service improperly handles hard links. An attacker who successfully exploited the vulnerability could cause a target system to stop responding. (CVE-2020-0789)
last seen2020-04-18
modified2020-03-10
plugin id134381
published2020-03-10
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/134381
titleSecurity Updates for Microsoft Visual Studio Products (March 2020)
code
#
# (C) Tenable Network Security, Inc.
#

# The descriptive text and package checks in this plugin were  
# extracted from the Microsoft Security Updates API. The text
# itself is copyright (C) Microsoft Corporation.
#

include('compat.inc');

if (description)
{
  script_id(134381);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/17");

  script_cve_id(
    "CVE-2020-0789",
    "CVE-2020-0793",
    "CVE-2020-0810",
    "CVE-2020-0884"
  );
  script_xref(name:"MSKB", value:"4538032");
  script_xref(name:"MSFT", value:"MS20-4538032");

  script_name(english:"Security Updates for Microsoft Visual Studio Products (March 2020)");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft Visual Studio Products are affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft Visual Studio Products are missing security
updates. It is, therefore, affected by multiple
vulnerabilities :

  - A spoofing vulnerability exists in Microsoft Visual
    Studio as it includes a reply URL that is not secured by
    SSL. An attacker who successfully exploited this
    vulnerability could compromise the access tokens,
    exposing security and privacy risks.  (CVE-2020-0884)

  - An elevation of privilege vulnerability exists when the
    Diagnostics Hub Standard Collector or the Visual Studio
    Standard Collector allows file creation in arbitrary
    locations.  (CVE-2020-0810)

  - An elevation of privilege vulnerability exists when the
    Diagnostics Hub Standard Collector Service improperly
    handles file operations. An attacker who successfully
    exploited this vulnerability could gain elevated
    privileges. An attacker with unprivileged access to a
    vulnerable system could exploit this vulnerability. The
    security update addresses the vulnerability by ensuring
    the Diagnostics Hub Standard Collector Service properly
    handles file operations. (CVE-2020-0793)

  - A denial of service vulnerability exists when the Visual
    Studio Extension Installer Service improperly handles
    hard links. An attacker who successfully exploited the
    vulnerability could cause a target system to stop
    responding.  (CVE-2020-0789)");
  # https://support.microsoft.com/en-us/help/4538032/march-10-2020-security-update-for-microsoft-visual-studio-2015
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?627290b1");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released the following security updates to address this issue:
  - KB4538032
  - Update 15.9.21 for Visual Studio 2017
  - Update 16.0.12 for Visual Studio 2019
  - Update 16.4.6 for Visual Studio 2019");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/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-2020-0793");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/03/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/03/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/03/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:visual_studio");
  script_end_attributes();

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

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

  script_dependencies("ms_bulletin_checks_possible.nasl", "microsoft_visual_studio_installed.nbin");
  script_require_keys("SMB/MS_Bulletin_Checks/Possible", "installed_sw/Microsoft Visual Studio");
  script_require_ports(139, 445, "Host/patch_management_checks");

  exit(0);
}

include('audit.inc');
include('misc_func.inc');
include('install_func.inc');
include('global_settings.inc');
include('smb_func.inc');
include('smb_hotfixes.inc');
include('smb_hotfixes_fcheck.inc');

get_kb_item_or_exit('installed_sw/Microsoft Visual Studio');

port = kb_smb_transport();
appname = 'Microsoft Visual Studio';

installs = get_installs(app_name:appname, exit_if_not_found:TRUE);

report = '';

foreach install (installs[1])
{
  version = install['version'];
  path = install['path'];
  prod = install['Product'];

  fix = '';

  # VS 2015 Up3
  if (version =~ '^14\\.0\\.')
  {
    patch_installed = false;
    foreach name (get_kb_list('SMB/Registry/HKLM/SOFTWARE/Microsoft/Windows/CurrentVersion/Uninstall/*/DisplayName'))
      if ('4538032' >< name)
        patch_installed = true;

    if (!patch_installed)
      report +=
        '\nNote: The fix for this issue is available in the following update:\n' +
        '\n  - KB4538032 : Security update for Microsoft Visual Studio 2015 Update 3: March 10, 2020\n' +
        '\n';
  }
  # VS 2017 (15.9)
  else if (prod == '2017' && version =~ '^15\\.[1-9]\\.')
  {
    fix = '15.9.28307.1064';

    if (ver_compare(ver: version, fix: fix, strict:FALSE) < 0)
    {
      report +=
        '\n  Path              : ' + path +
        '\n  Installed version : ' + version +
        '\n  Fixed version     : ' + fix +
        '\n';
    }
  }
  # VS 2019 Version 16.0
  else if (prod == '2019' && version =~ '^16\\.0\\.')
  {
    fix = '16.0.28803.697';
    if (ver_compare(ver: version, fix: fix, strict:FALSE) < 0)
    {
      report +=
        '\n  Path              : ' + path +
        '\n  Installed version : ' + version +
        '\n  Fixed version     : ' + fix +
        '\n';
    }
  }
  # VS 2019 Version 16.4
  else if (prod == '2019' && version =~ '^16\\.4\\.')
  {
    fix = '16.4.29905.134';
    if (ver_compare(ver: version, fix: fix, strict:FALSE) < 0)
    {
      report +=
        '\n  Path              : ' + path +
        '\n  Installed version : ' + version +
        '\n  Fixed version     : ' + fix +
        '\n';
    }
  }
}

if (empty(report))
  audit(AUDIT_INST_VER_NOT_VULN, appname);

security_report_v4(port:port, severity:SECURITY_HOLE, extra:report);