Vulnerabilities > CVE-2019-0956 - Improper Encoding or Escaping of Output vulnerability in Microsoft products

047910
CVSS 4.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
SINGLE
Confidentiality impact
PARTIAL
Integrity impact
NONE
Availability impact
NONE
network
low complexity
microsoft
CWE-116
nessus

Summary

An information disclosure vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka 'Microsoft SharePoint Server Information Disclosure Vulnerability'.

Vulnerable Configurations

Part Description Count
Application
Microsoft
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Embedding Scripts in Non-Script Elements
    This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an attacker to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote attacker to collect and interpret the output of said attack.
  • Simple Script Injection
    An attacker embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.
  • User-Controlled Filename
    An attack of this type involves an attacker inserting malicious characters (such as a XSS redirection) into a filename, directly or indirectly that is then used by the target software to generate HTML text or other potentially executable content. Many websites rely on user-generated content and dynamically build resources like files, filenames, and URL links directly from user supplied data. In this attack pattern, the attacker uploads code that can execute in the client browser and/or redirect the client browser to a site that the attacker owns. All XSS attack payload variants can be used to pass and exploit these vulnerabilities.
  • Web Logs Tampering
    Web Logs Tampering attacks involve an attacker injecting, deleting or otherwise tampering with the contents of web logs typically for the purposes of masking other malicious behavior. Additionally, writing malicious data to log files may target jobs, filters, reports, and other agents that process the logs in an asynchronous attack pattern. This pattern of attack is similar to "Log Injection-Tampering-Forging" except that in this case, the attack is targeting the logs of the web server and not the application.

Nessus

NASL familyWindows : Microsoft Bulletins
NASL idSMB_NT_MS19_MAY_OFFICE_SHAREPOINT.NASL
descriptionThe Microsoft SharePoint Server installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities : - An information disclosure vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server. An authenticated attacker could exploit the vulnerability by sending a specially crafted request to an affected SharePoint server. The attacker who successfully exploited the vulnerability could then perform cross-site scripting attacks on affected systems and run script in the security context of the current user. These attacks could allow the attacker to read content that the attacker is not authorized to read, use the victim
last seen2020-06-01
modified2020-06-02
plugin id125227
published2019-05-16
reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/125227
titleSecurity Updates for Microsoft SharePoint Server (May 2019)
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(125227);
  script_version("1.5");
  script_cvs_date("Date: 2019/12/06");

  script_cve_id(
    "CVE-2019-0949",
    "CVE-2019-0950",
    "CVE-2019-0951",
    "CVE-2019-0952",
    "CVE-2019-0956",
    "CVE-2019-0957",
    "CVE-2019-0958",
    "CVE-2019-0963"
  );
  script_bugtraq_id(
    108198,
    108201,
    108203,
    108209,
    108213,
    108215,
    108216,
    108218
  );
  script_xref(name:"MSKB", value:"4464573");
  script_xref(name:"MSKB", value:"4464564");
  script_xref(name:"MSKB", value:"4464556");
  script_xref(name:"MSKB", value:"4464549");
  script_xref(name:"MSFT", value:"MS19-4464573");
  script_xref(name:"MSFT", value:"MS19-4464564");
  script_xref(name:"MSFT", value:"MS19-4464556");
  script_xref(name:"MSFT", value:"MS19-4464549");

  script_name(english:"Security Updates for Microsoft SharePoint Server (May 2019)");
  script_summary(english:"Checks for Microsoft security updates.");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft SharePoint Server installation on the remote host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft SharePoint Server installation on the remote
host is missing security updates. It is, therefore, affected
by multiple vulnerabilities :

  - An information disclosure vulnerability exists when
    Microsoft SharePoint Server does not properly sanitize a
    specially crafted web request to an affected SharePoint
    server. An authenticated attacker could exploit the
    vulnerability by sending a specially crafted request to
    an affected SharePoint server. The attacker who
    successfully exploited the vulnerability could then
    perform cross-site scripting attacks on affected systems
    and run script in the security context of the current
    user. These attacks could allow the attacker to read
    content that the attacker is not authorized to read, use
    the victim's identity to take actions on the SharePoint
    site on behalf of the user, such as change permissions
    and delete content, and inject malicious content in the
    browser of the user. The security update addresses the
    vulnerability by helping to ensure that SharePoint
    Server properly sanitizes web requests. (CVE-2019-0956)

  - An elevation of privilege vulnerability exists when
    Microsoft SharePoint Server does not properly sanitize a
    specially crafted web request to an affected SharePoint
    server. An authenticated attacker could exploit the
    vulnerability by sending a specially crafted request to
    an affected SharePoint server. The attacker who
    successfully exploited the vulnerability could then
    perform cross-site scripting attacks on affected systems
    and run script in the security context of the current
    user. These attacks could allow the attacker to read
    content that the attacker is not authorized to read, use
    the victim's identity to take actions on the SharePoint
    site on behalf of the user, such as change permissions
    and delete content, and inject malicious content in the
    browser of the user. The security update addresses the
    vulnerability by helping to ensure that SharePoint
    Server properly sanitizes web requests. (CVE-2019-0957,
    CVE-2019-0958)

  - A remote code execution vulnerability exists in
    Microsoft SharePoint Server when it fails to properly
    identify and filter unsafe ASP.Net web controls. An
    authenticated attacker who successfully exploited the
    vulnerability could use a specially crafted page to
    perform actions in the security context of the
    SharePoint application pool process.  (CVE-2019-0952)

  - A cross-site-scripting (XSS) vulnerability exists when
    Microsoft SharePoint Server does not properly sanitize a
    specially crafted web request to an affected SharePoint
    server. An authenticated attacker could exploit the
    vulnerability by sending a specially crafted request to
    an affected SharePoint server. The attacker who
    successfully exploited the vulnerability could then
    perform cross-site scripting attacks on affected systems
    and run script in the security context of the current
    user. The attacks could allow the attacker to read
    content that the attacker is not authorized to read, use
    the victim's identity to take actions on the SharePoint
    site on behalf of the user, such as change permissions
    and delete content, and inject malicious content in the
    browser of the user. The security update addresses the
    vulnerability by helping to ensure that SharePoint
    Server properly sanitizes web requests. (CVE-2019-0963)

  - A spoofing vulnerability exists when Microsoft
    SharePoint Server does not properly sanitize a specially
    crafted web request to an affected SharePoint server. An
    authenticated attacker could exploit the vulnerability
    by sending a specially crafted request to an affected
    SharePoint server. The attacker who successfully
    exploited the vulnerability could then perform cross-
    site scripting attacks on affected systems and run
    script in the security context of the current user.
    These attacks could allow the attacker to read content
    that the attacker is not authorized to read, use the
    victim's identity to take actions on the SharePoint site
    on behalf of the user, such as change permissions and
    delete content, and inject malicious content in the
    browser of the user. The security update addresses the
    vulnerability by helping to ensure that SharePoint
    Server properly sanitizes web requests. (CVE-2019-0949,
    CVE-2019-0950, CVE-2019-0951)");
  # https://support.microsoft.com/en-ie/help/4464573/description-of-the-security-update-for-sharepoint-foundation-2010-may
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?cd24cf15");
  # https://support.microsoft.com/en-ie/help/4464564/description-of-the-security-update-for-sharepoint-foundation-2013-may
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?10270ee1");
  # https://support.microsoft.com/en-us/help/4464556/description-of-the-security-update-for-sharepoint-server-2019-may-14
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2f5a91df");
  # https://support.microsoft.com/en-us/help/4464549/description-of-the-security-update-for-sharepoint-enterprise-server
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f305a65b");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released the following security updates to address this issue:  
  -KB4464573
  -KB4464564
  -KB4464556
  -KB4464549");
  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:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/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-2019-0958");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/05/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/05/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/05/16");

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

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

  script_copyright(english:"This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("microsoft_sharepoint_installed.nbin","smb_hotfixes.nasl","ms_bulletin_checks_possible.nasl");
  script_require_keys("SMB/MS_Bulletin_Checks/Possible");
  script_require_ports(139, 445, "Host/patch_management_checks");

  exit(0);
}

include('smb_func.inc');
include('smb_hotfixes.inc');
include('smb_hotfixes_fcheck.inc');
include('smb_reg_query.inc');
include('misc_func.inc');
include('install_func.inc');
include('lists.inc');

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

bulletin = 'MS19-05';

kbs = make_list(
  '4464549', # 2016
  '4464556', # 2019
  '4464564', # 2013
  '4464573'  # 2010
);

if (get_kb_item('Host/patch_management_checks'))
  hotfix_check_3rd_party(bulletin:bulletin, kbs:kbs, severity:SECURITY_WARNING);

get_kb_item_or_exit('SMB/Registry/Enumerated', exit_code:1);

# Get path information for Windows.
windir = hotfix_get_systemroot();
if (isnull(windir)) exit(1, 'Failed to determine the location of %windir%.');

registry_init();

vuln = FALSE;
port = kb_smb_transport();

install = get_single_install(app_name:'Microsoft SharePoint Server');

# direct reference lookup of product...
kb_checks =
{
  '2010':
  # direct reference lookup of SP...
  { '2':
    # direct reference lookup of edition...
    { 'Foundation':
      [{
        'kb'           : '4464573',
        'path'         : hotfix_get_commonfilesdir(),
        'append'       : 'microsoft shared\\web server extensions\\14\\isapi',
        'file'         : 'microsoft.sharepoint.dll',
        'version'      : '14.0.7235.5000',
        'product_name' : 'Microsoft SharePoint Foundation Server 2010 SP 2'
      }]
    }
  },
  '2013':
  # direct reference lookup of SP...
  { '1':
    # direct reference lookup of edition...
    { 'Foundation':
      [{
        'kb'           : '4464564',
        'path'         : hotfix_get_commonfilesdir(),
        'append'       : 'microsoft shared\\Web Server Extensions\\15\\config\\bin',
        'file'         : 'stssoap.dll',
        'version'      : '15.0.4981.1000',
        'product_name' : 'Microsoft SharePoint Foundation Server 2013 SP 1'
      }]
    }
  },
  '2016':
  # direct reference lookup of SP...
  { '0':
    # direct reference lookup of edition...
    { 'Server':
      [{
        'kb'           : '4464549',
        'path'         : install['path'],
        'append'       : 'TransformApps',
        'file'         : 'docxpageconverter.exe',
        'version'      : '16.0.4849.1000',
        'product_name' : 'Microsoft SharePoint Server 2016'
      }]
    }
  },
  '2019':
  # direct reference lookup of SP...
  { '0':
    # direct reference lookup of edition...
    { 'Server':
      [{
        'kb'           : '4464556',
        'path'         : install['path'],
        'append'       : 'BIN',
        'file'         : 'ascalc.dll',
        'version'      : '16.0.10345.12101',
        'product_name' : 'Microsoft SharePoint Enterprise Server 2019'
      }]
    }
  }
};

# get the specific product / path 
params = kb_checks[install['Product']][install['SP']][install['Edition']][0];
# audit if not affected
if (isnull(params)) audit(AUDIT_INST_VER_NOT_VULN, "Microsoft SharePoint Server");

are_we_vuln = HCF_OLDER;

# grab the path otherwise
path = hotfix_append_path(path:params['path'], value:params['append']);
# then - check if we are vuln
are_we_vuln = hotfix_check_fversion(file:params['file'], version:params['version'], path:path, kb:params['kb'], product:params['product_name']);

if (are_we_vuln != HCF_OK && params['kb'] == '4464573' && get_kb_item("SMB/Registry/Uninstall/Enumerated"))
{
  display_names = get_kb_list_or_exit('SMB/Registry/HKLM/SOFTWARE/Microsoft/Windows/CurrentVersion/Uninstall/*/DisplayName');
  if (display_names)
  {
    foreach item (keys(display_names))
    {
      if ('KB'+params['kb'] >< display_names[item])
      {
        are_we_vuln = HCF_OK;
        break;
      }
    }

    if (are_we_vuln)
    {
      report = '\n';
      if (params['product_name'])
        report += '  Product : ' + params['product_name'] + '\n';
      if (params['kb'])
        report += '  KB : ' + params['kb'] + '\n';
      hotfix_add_report(report, kb:params['kb']);
    }
  }
}

xss = FALSE;

if (params['kb'] == '4464564')
  xss = TRUE;

if (are_we_vuln == HCF_OLDER)
{
  replace_kb_item(name:'SMB/Missing/'+bulletin, value:TRUE);
  if (xss) replace_kb_item(name:'www/'+port+'/XSS', value:TRUE);
  hotfix_security_warning();
  hotfix_check_fversion_end();
  exit(0);
}
else
{
  hotfix_check_fversion_end();
  audit(AUDIT_HOST_NOT, 'affected');
}