Vulnerabilities > CVE-2019-0957 - Improper Input Validation vulnerability in Microsoft Sharepoint Enterprise Server and Sharepoint Server

047910
CVSS 8.8 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
LOW
Confidentiality impact
HIGH
Integrity impact
HIGH
Availability impact
HIGH
network
low complexity
microsoft
CWE-20
nessus
NVD
Published: 2019-05-16
Updated: 2020-08-24

Summary

An elevation of privilege vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka 'Microsoft SharePoint Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0958.

Vulnerable Configurations

Part Description Count
Application
Microsoft
2

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • 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.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

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');
}

References