Vulnerabilities > CVE-2020-0651 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Microsoft Excel and Office 365 Proplus

047910
CVSS 9.3 - CRITICAL
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
microsoft
CWE-119
critical
nessus

Summary

A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory, aka 'Microsoft Excel Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0650, CVE-2020-0653.

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.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Nessus

  • NASL familyWindows : Microsoft Bulletins
    NASL idSMB_NT_MS20_JAN_EXCEL.NASL
    descriptionThe Microsoft Excel Products are missing security updates. It is, therefore, affected by multiple vulnerabilities : - A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. (CVE-2020-0650, CVE-2020-0651)
    last seen2020-06-01
    modified2020-06-02
    plugin id132867
    published2020-01-14
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/132867
    titleSecurity Updates for Microsoft Excel Products (January 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(132867);
      script_version("1.6");
      script_cvs_date("Date: 2020/02/14");
    
      script_cve_id("CVE-2020-0650", "CVE-2020-0651");
      script_xref(name:"MSKB", value:"4484234");
      script_xref(name:"MSKB", value:"4484217");
      script_xref(name:"MSKB", value:"4484243");
      script_xref(name:"MSFT", value:"MS20-4484234");
      script_xref(name:"MSFT", value:"MS20-4484217");
      script_xref(name:"MSFT", value:"MS20-4484243");
    
      script_name(english:"Security Updates for Microsoft Excel Products (January 2020)");
    
      script_set_attribute(attribute:"synopsis", value:
    "The Microsoft Excel Products are affected by multiple vulnerabilities.");
      script_set_attribute(attribute:"description", value:
    "The Microsoft Excel Products are missing security updates.
    It is, therefore, affected by multiple vulnerabilities :
    
      - A remote code execution vulnerability exists in
        Microsoft Excel software when the software fails to
        properly handle objects in memory. An attacker who
        successfully exploited the vulnerability could run
        arbitrary code in the context of the current user. If
        the current user is logged on with administrative user
        rights, an attacker could take control of the affected
        system. An attacker could then install programs; view,
        change, or delete data; or create new accounts with full
        user rights.  (CVE-2020-0650, CVE-2020-0651)");
      script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/en-us/help/4484234");
      script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/en-us/help/4484217");
      script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/en-us/help/4484243");
      script_set_attribute(attribute:"solution", value:
    "Microsoft has released the following security updates to address this issue:  
      -KB4484234
      -KB4484217
      -KB4484243
    For Office 365, Office 2016 C2R, or Office 2019, ensure automatic updates 
    are enabled or open any office app and manually perform an update.");
    
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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:N/UI:R/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-2020-0650");
    
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/14");
      script_set_attribute(attribute:"patch_publication_date", value:"2020/01/14");
      script_set_attribute(attribute:"plugin_publication_date", value:"2020/01/14");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:excel");
      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("office_installed.nasl", "microsoft_office_compatibility_pack_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('audit.inc');
    include('smb_func.inc');
    include('smb_hotfixes.inc');
    include('smb_hotfixes_fcheck.inc');
    include('smb_reg_query.inc');
    include('install_func.inc');
    
    global_var vuln;
    
    get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');
    
    bulletin = 'MS20-01';
    kbs = make_list(
      '4484234',
      '4484217',
      '4484243'
    );
    
    if (get_kb_item('Host/patch_management_checks'))
      hotfix_check_3rd_party(bulletin:bulletin, kbs:kbs, severity:SECURITY_HOLE);
    
    get_kb_item_or_exit('SMB/Registry/Enumerated', exit_code:1);
    
    port = kb_smb_transport();
    
    checks = make_array(
      '15.0', make_array('sp', 1, 'version', '15.0.5207.1000', 'kb', '4484234'),
      '14.0', make_array('sp', 2, 'version', '14.0.7244.5000', 'kb', '4484243'),
      '16.0', make_nested_list(make_array('sp', 0, 'version', '16.0.4954.1000', 'channel', 'MSI', 'kb', '4484217'),
        # C2R
        make_array("version", "16.0.10730.20432", "channel", "Deferred"),
        make_array("version", "16.0.11328.20512", "channel", "Deferred", "channel_version", "1902"),
        make_array("version", "16.0.11929.20562", "channel", "First Release for Deferred"),
        make_array("version", "16.0.12325.20298", "channel", "Current"),
        # 2019
        make_array("version", "16.0.12325.20298", "channel", "2019 Retail"),
        make_array("version", "16.0.10354.20022", "channel", "2019 Volume"))
      );
    
    if (hotfix_check_office_product(product:'Excel', checks:checks, bulletin:bulletin))
    {
      replace_kb_item(name:'SMB/Missing/'+bulletin, value:TRUE);
      hotfix_security_hole();
      hotfix_check_fversion_end();
      exit(0);
    }
    else
    {
      hotfix_check_fversion_end();
      audit(AUDIT_HOST_NOT, 'affected');
    }
    
  • NASL familyMacOS X Local Security Checks
    NASL idMACOS_MS20_JAN_OFFICE.NASL
    descriptionThe Microsoft Office application installed on the remote macOS or Mac OS X host is missing a security update. It is, therefore, affected by multiple vulnerabilities: - A remote code execution vulnerability exists when Microsoft Excel improperly handles objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. To exploit the vulnerability, an attacker has to entice the logged on user to click a link or open a specially crafted file to gain control of the system with the priviledges of the logged on user. (CVE-2020-0650 CVE-2020-0651)
    last seen2020-06-01
    modified2020-06-02
    plugin id132938
    published2020-01-15
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/132938
    titleSecurity Updates for Microsoft Office Products (January 2020) (macOS)
    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(132938);
      script_version("1.6");
      script_cvs_date("Date: 2020/02/14");
    
      script_cve_id("CVE-2020-0650", "CVE-2020-0651");
      script_xref(name:"IAVA", value:"2020-A-0029");
    
      script_name(english:"Security Updates for Microsoft Office Products (January 2020) (macOS)");
      script_summary(english:"Checks the version of Microsoft Office.");
    
      script_set_attribute(attribute:"synopsis", value:
    "An application installed on the remote macOS or Mac OS X host is affected by multiple vulnerabilities");
      script_set_attribute(attribute:"description", value:
    "The Microsoft Office application installed on the remote macOS or Mac OS X host is missing a security update. It is,
    therefore, affected by multiple vulnerabilities:
    
      - A remote code execution vulnerability exists when Microsoft Excel
       improperly handles objects in memory. An attacker who successfully
       exploited the vulnerability could run arbitrary code in the context
       of the current user. To exploit the vulnerability, an attacker has to
       entice the logged on user to click a link or open a specially crafted
       file to gain control of the system with the priviledges of the logged
       on user. (CVE-2020-0650 CVE-2020-0651)");
      # https://docs.microsoft.com/en-us/officeupdates/update-history-office-for-mac
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?43ed1b90");
      # https://docs.microsoft.com/en-us/officeupdates/release-notes-office-for-mac#january-14-2020
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?21a62786");
      # https://docs.microsoft.com/en-us/officeupdates/release-notes-office-2016-mac
      script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dae26676");
      script_set_attribute(attribute:"solution", value:
    "Microsoft has released a set of patches for Microsoft Office for Mac.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/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:N/UI:R/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-2020-0651");
    
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2020/01/14");
      script_set_attribute(attribute:"patch_publication_date", value:"2020/01/14");
      script_set_attribute(attribute:"plugin_publication_date", value:"2020/01/15");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:apple:mac_os_x");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:office");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:excel");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:word");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:powerpoint");
      script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:outlook");
      script_set_attribute(attribute:"stig_severity", value:"II");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_family(english:"MacOS X Local Security Checks");
    
      script_copyright(english:"This script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
    
      script_dependencies("macosx_office_installed.nbin");
      script_require_keys("Host/MacOSX/Version");
      script_require_ports("installed_sw/Microsoft Word", "installed_sw/Microsoft Excel", "installed_sw/Microsoft PowerPoint", "installed_sw/Microsoft OneNote", "installed_sw/Microsoft Outlook");
    
      exit(0);
    }
    include('audit.inc');
    include('global_settings.inc');
    include('misc_func.inc');
    include('install_func.inc');
    include('vcf.inc');
    
    os = get_kb_item_or_exit('Host/MacOSX/Version');
    apps = make_list(
      'Microsoft Word',
      'Microsoft Excel',
      'Microsoft PowerPoint',
      'Microsoft Outlook'
    );
    report = '';
    
    #2016
    min_ver_16 = '16';
    fix_ver_16 = '16.16.18';
    fix_disp_16 = '16.16.18 (20011202)';
    
    #2019
    min_ver_19 = '16.17.0';
    fix_ver_19 = '16.33';
    fix_disp_19 = '16.33 (20011301)';
    
    foreach app (apps)
    {
      installs = get_installs(app_name:app);
      if (isnull(installs[1]))
        continue;
    
      foreach install (installs[1])
      {
        version = install['version'];
    
        if (ver_compare(ver:version, minver:min_ver_19, fix:fix_ver_19, strict:FALSE) < 0)
        {
          app_label = app + ' for Mac 2019';
          report +=
            '\n\n  Product           : ' + app_label +
            '\n  Installed version : ' + version +
            '\n  Fixed version     : ' + fix_disp_19;
        }
        else if (ver_compare(ver:version, minver:min_ver_16, fix:fix_ver_16, strict:FALSE) < 0)
        {
          app_label = app + ' for Mac 2016';
          report +=
            '\n\n  Product           : ' + app_label +
            '\n  Installed version : ' + version +
            '\n  Fixed version     : ' + fix_disp_16;
        }
      }
    }
    if (empty(report))
      audit(AUDIT_HOST_NOT, 'affected');
    
    if (os =~ "^Mac OS X 10\.[0-9](\.|$)")
      report += '\n  Note              : Update will require Mac OS X 10.10.0 or later.\n';
    
    security_report_v4(severity:SECURITY_HOLE, port:0, extra:report);