Vulnerabilities > CVE-2020-0991 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Microsoft Office 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
NVD
Published: 2020-04-15
Updated: 2021-07-21

Summary

A remote code execution vulnerability exists in Microsoft Office software when the software fails to properly handle objects in memory, aka 'Microsoft Office Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-0760.

Vulnerable Configurations

Part Description Count
Application
Microsoft
6

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.
  • 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_APR_OFFICE.NASL
descriptionThe Microsoft Office Products are missing security updates. It is, therefore, affected by multiple vulnerabilities : - A remote code execution vulnerability exists when Microsoft Office improperly loads arbitrary type libraries. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. (CVE-2020-0760) - A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user. (CVE-2020-0980) - A remote code execution vulnerability exists in Microsoft Office 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-2020-0991) - A remote code execution vulnerability exists when the Microsoft Office Access Connectivity Engine improperly handles objects in memory. An attacker who successfully exploited this vulnerability could execute arbitrary code on a victim system. An attacker could exploit this vulnerability by enticing a victim to open a specially crafted file. The update addresses the vulnerability by correcting the way the Microsoft Office Access Connectivity Engine handles objects in memory. (CVE-2020-0961) - 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-2020-0906, CVE-2020-0979)
last seen2020-04-18
modified2020-04-14
plugin id135476
published2020-04-14
reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/135476
titleSecurity Updates for Microsoft Office Products (April 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(135476);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/04/17");

  script_cve_id(
    "CVE-2020-0760",
    "CVE-2020-0906",
    "CVE-2020-0961",
    "CVE-2020-0979",
    "CVE-2020-0980",
    "CVE-2020-0991"
  );
  script_xref(name:"MSKB", value:"3128012");
  script_xref(name:"MSKB", value:"3203462");
  script_xref(name:"MSKB", value:"4011104");
  script_xref(name:"MSKB", value:"4484117");
  script_xref(name:"MSKB", value:"4484126");
  script_xref(name:"MSKB", value:"4484214");
  script_xref(name:"MSKB", value:"4484229");
  script_xref(name:"MSKB", value:"4484238");
  script_xref(name:"MSKB", value:"4484258");
  script_xref(name:"MSKB", value:"4484260");
  script_xref(name:"MSKB", value:"4484266");
  script_xref(name:"MSKB", value:"4484287");
  script_xref(name:"MSKB", value:"4484294");
  script_xref(name:"MSFT", value:"MS20-3128012");
  script_xref(name:"MSFT", value:"MS20-3203462");
  script_xref(name:"MSFT", value:"MS20-4011104");
  script_xref(name:"MSFT", value:"MS20-4484117");
  script_xref(name:"MSFT", value:"MS20-4484126");
  script_xref(name:"MSFT", value:"MS20-4484214");
  script_xref(name:"MSFT", value:"MS20-4484229");
  script_xref(name:"MSFT", value:"MS20-4484238");
  script_xref(name:"MSFT", value:"MS20-4484258");
  script_xref(name:"MSFT", value:"MS20-4484260");
  script_xref(name:"MSFT", value:"MS20-4484266");
  script_xref(name:"MSFT", value:"MS20-4484287");
  script_xref(name:"MSFT", value:"MS20-4484294");
  script_xref(name:"IAVA", value:"2020-A-0142");

  script_name(english:"Security Updates for Microsoft Office Products (April 2020)");

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

  - A remote code execution vulnerability exists when
    Microsoft Office improperly loads arbitrary type
    libraries. An attacker could then install programs;
    view, change, or delete data; or create new accounts
    with full user rights. Users whose accounts are
    configured to have fewer user rights on the system could
    be less impacted than users who operate with
    administrative user rights.  (CVE-2020-0760)

  - A remote code execution vulnerability exists in
    Microsoft Word software when it fails to properly handle
    objects in memory. An attacker who successfully
    exploited the vulnerability could use a specially
    crafted file to perform actions in the security context
    of the current user. For example, the file could then
    take actions on behalf of the logged-on user with the
    same permissions as the current user.  (CVE-2020-0980)

  - A remote code execution vulnerability exists in
    Microsoft Office 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-2020-0991)

  - A remote code execution vulnerability exists when the
    Microsoft Office Access Connectivity Engine improperly
    handles objects in memory. An attacker who successfully
    exploited this vulnerability could execute arbitrary
    code on a victim system. An attacker could exploit this
    vulnerability by enticing a victim to open a specially
    crafted file. The update addresses the vulnerability by
    correcting the way the Microsoft Office Access
    Connectivity Engine handles objects in memory.
    (CVE-2020-0961)

  - 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-2020-0906, CVE-2020-0979)");
  # https://support.microsoft.com/en-us/help/3128012/security-update-for-office-2016-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c6907f9f");
  # https://support.microsoft.com/en-us/help/4484214/security-update-for-office-2016-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?22455c7d");
  # https://support.microsoft.com/en-us/help/4484260/security-update-for-office-2013-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6758cebc");
  # https://support.microsoft.com/en-us/help/4484266/security-update-for-office-2010-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?19ff4b0c");
  # https://support.microsoft.com/en-us/help/4484287/security-update-for-office-2016-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?acbb3d03");
  # https://support.microsoft.com/en-us/help/4484294/security-update-for-office-2010-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5e18eb45");
  # https://support.microsoft.com/en-us/help/3203462/security-update-for-office-2010-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?87117772");
  # https://support.microsoft.com/en-us/help/4484258/security-update-for-office-2016-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?cc8824f1");
  # https://support.microsoft.com/en-us/help/4484126/security-update-for-office-2010-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a0a366b9");
  # https://support.microsoft.com/en-us/help/4011104/security-update-for-office-2013-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?ee0e9939");
  # https://support.microsoft.com/en-us/help/4484117/security-update-for-office-2013-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?318ce33a");
  # https://support.microsoft.com/en-us/help/4484238/security-update-for-office-2010-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?872a2ed0");
  # https://support.microsoft.com/en-us/help/4484229/security-update-for-office-2013-april-14-2020
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?67e5e2db");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released security updates for Microsoft Office Products.

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-2020-0760");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/04/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/04/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/04/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:office");
  script_set_attribute(attribute:"stig_severity", value:"II");
  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", "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('install_func.inc');

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

bulletin = 'MS20-04';
kbs = make_list(
  '3203462', # Office 2010 SP2
  '4484126', # Office 2010 SP2
  '4484238', # Office 2010 SP2
  '4484266', # Office 2010 SP2
  '4484294', # Office 2010 SP2
  '4011104', # Office 2013 SP1
  '4484117', # Office 2013 SP1
  '4484229', # Office 2013 SP1
  '4484260', # Office 2013 SP1
  '3128012', # Office 2016
  '4484214', # Office 2016
  '4484287', # Office 2016
  '4484258'  # Office 2016
);

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);

vuln = FALSE;
port = kb_smb_transport();

office_vers = hotfix_check_office_version();

# Office 2010 SP2
if (office_vers['14.0'])
{
  office_sp = get_kb_item('SMB/Office/2010/SP');
  if (!isnull(office_sp) && office_sp == 2)
  {
    prod = 'Microsoft Office 2010 SP2';

    path = hotfix_get_officecommonfilesdir(officever:'14.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\VBA\\VBA7');
    kb = '3203462';
    file = 'vbe7.dll';
    version = '7.0.16.45';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'14.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE14');
    kb = '4484126';
    file = 'mso.dll';
    version = '14.0.7248.5000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'14.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE14');
    kb = '4484238';
    file = 'acecore.dll';
    version = '14.0.7248.5000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officeprogramfilesdir(officever:'14.0');
    path = hotfix_append_path(path:path, value:'Microsoft Office\\Office14');
    kb = '4484266';
    file = 'graph.exe';
    version = '14.0.7248.5000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    # wwlibcxm.dll only exists if KB2428677 is installed
    path = hotfix_get_officeprogramfilesdir(officever:'14.0');
    path = hotfix_append_path(path:path, value:'Microsoft Office\\Office14');
    kb = '4484294';
    file = 'wwlibcxm.dll';
    version = '14.0.7248.5000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

  }
}

# Office 2013 SP1
if (office_vers['15.0'])
{
  office_sp = get_kb_item('SMB/Office/2013/SP');
  if (!isnull(office_sp) && office_sp == 1)
  {
    prod = 'Microsoft Office 2013 SP1';

    path = hotfix_get_officecommonfilesdir(officever:'15.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\VBA\\VBA7.1');
    kb = '4011104';
    file = 'vbe7.dll';
    version = '7.1.10.96';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER )
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'15.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE15');
    kb = '4484117';
    file = 'mso.dll';
    version = '15.0.5233.1000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER )
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'15.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE15');
    kb = '4484229';
    file = 'acecore.dll';
    version = '15.0.5233.1000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER )
      vuln = TRUE;

    path = hotfix_get_officeprogramfilesdir(officever:'15.0');
    path = hotfix_append_path(path:path, value:'Microsoft Office\\Office15');
    kb = '4484260';
    file = 'graph.exe';
    version = '15.0.5233.1000';
    if (hotfix_check_fversion(file:file, version:version, path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER )
      vuln = TRUE;
  }
}

# Office 2016 / 2019 / C2R
if (office_vers['16.0'])
{
  office_sp = get_kb_item('SMB/Office/2016/SP');
  if (!isnull(office_sp) && office_sp == 0)
  {
    prod = 'Microsoft Office 2016';

    path = hotfix_get_officecommonfilesdir(officever:'16.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\VBA\\VBA7.1');
    kb = '3128012';
    file = 'vbe7.dll';
    version = '7.1.10.96';
    if (hotfix_check_fversion(file:file, version:version, channel:'MSI', channel_product:'Office', path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'16.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE16');
    kb = '4484214';
    file = 'mso.dll';
    version = '16.0.4993.1002';
    if (hotfix_check_fversion(file:file, version:version, channel:'MSI', channel_product:'Office', path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officecommonfilesdir(officever:'16.0');
    path = hotfix_append_path(path:path, value:'Microsoft Shared\\OFFICE16');
    kb = '4484287';
    file = 'acecore.dll';
    version = '16.0.4993.1000';
    if (hotfix_check_fversion(file:file, version:version, channel:'MSI', channel_product:'Office', path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    path = hotfix_get_officeprogramfilesdir(officever:'16.0');
    path = hotfix_append_path(path:path, value:'Microsoft Office\\Office16');
    kb = '4484258';
    file = 'graph.exe';
    version = '16.0.4993.1000';
    if (hotfix_check_fversion(file:file, version:version, channel:'MSI', channel_product:'Office', path:path, kb:kb, bulletin:bulletin, product:prod) == HCF_OLDER)
      vuln = TRUE;

    prod2019 = 'Microsoft Office 2019';
    path = hotfix_get_officeprogramfilesdir(officever:'16.0');
    path = hotfix_append_path(path:path, value:'Microsoft Office\\root\\Office16');
    if (
      hotfix_check_fversion(file:'graph.exe', version:'16.0.11328.20564', channel:'Deferred', channel_product:'Office', path:path, bulletin:bulletin, product:prod) == HCF_OLDER ||
      hotfix_check_fversion(file:'graph.exe', version:'16.0.11929.20708', channel:'Deferred', channel_version:'1908', channel_product:'Office', path:path, bulletin:bulletin, product:prod) == HCF_OLDER ||
      hotfix_check_fversion(file:'graph.exe', version:'16.0.12527.20442', channel:'First Release for Deferred', channel_product:'Office', path:path, bulletin:bulletin, product:prod) == HCF_OLDER ||
      hotfix_check_fversion(file:'graph.exe', version:'16.0.12624.20442', channel:'Current', channel_product:'Office', path:path, bulletin:bulletin, product:prod) == HCF_OLDER ||
      # 2019
      hotfix_check_fversion(file:'graph.exe', version:'16.0.12624.20442', channel:'2019 Retail', channel_product:'Office', path:path, bulletin:bulletin, product:prod2019) == HCF_OLDER ||
      hotfix_check_fversion(file:'graph.exe', version:'16.0.10358.20061', channel:'2019 Volume', channel_product:'Office', path:path, bulletin:bulletin, product:prod2019) == HCF_OLDER
    )
    vuln = TRUE;
  }
}

if (vuln)
{
  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');
}

References