KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update - Nessus

Critical Plugin ID: 147231

This page contains detailed information about the KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update Nessus plugin including available exploits and PoCs found on GitHub, in Metasploit or Exploit-DB for verifying of this vulnerability.

Table Of Contents

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Plugin Overview
Vulnerability Information

Synopsis
Description
Solution

Public Exploits
Risk Information
Plugin Source
How to Run
References
Version

Plugin Overview

ID: 147231
Name: KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update
Filename: smb_nt_ms21_mar_5000841.nasl
Vulnerability Published: 2021-03-08
This Plugin Published: 2021-03-09
Last Modification Time: 2021-11-30
Plugin Version: 1.8
Plugin Type: local
Plugin Family: Windows : Microsoft Bulletins
Dependencies: ms_bulletin_checks_possible.nasl, smb_check_rollup.nasl, smb_hotfixes.nasl
Required KB Items [?]: SMB/MS_Bulletin_Checks/Possible

Vulnerability Information

Severity: Critical
Vulnerability Published: 2021-03-08
Patch Published: 2021-03-08
CVE [?]: CVE-2021-1640, CVE-2021-24107, CVE-2021-26411, CVE-2021-26861, CVE-2021-26862, CVE-2021-26869, CVE-2021-26872, CVE-2021-26873, CVE-2021-26875, CVE-2021-26877, CVE-2021-26878, CVE-2021-26881, CVE-2021-26882, CVE-2021-26893, CVE-2021-26894, CVE-2021-26895, CVE-2021-26896, CVE-2021-26897, CVE-2021-26898, CVE-2021-26899, CVE-2021-26901, CVE-2021-27063, CVE-2021-27077
CPE [?]: cpe:/o:microsoft:windows
Exploited by Malware: True

Synopsis

The remote Windows host is affected by multiple vulnerabilities.

Description

The remote Windows host is missing security update 5000851 or cumulative update 5000841. It is, therefore, affected by multiple vulnerabilities :

- A remote code execution vulnerability. An attacker can exploit this to bypass authentication and execute unauthorized arbitrary commands. (CVE-2021-26861, CVE-2021-26877, CVE-2021-26881, CVE-2021-26893, CVE-2021-26894, CVE-2021-26895, CVE-2021-26897)

- An information disclosure vulnerability. An attacker can exploit this to disclose potentially sensitive information. (CVE-2021-24107, CVE-2021-26869)

- An elevation of privilege vulnerability. An attacker can exploit this to gain elevated privileges. (CVE-2021-1640, CVE-2021-26862, CVE-2021-26872, CVE-2021-26873, CVE-2021-26875, CVE-2021-26878, CVE-2021-26882, CVE-2021-26898, CVE-2021-26899, CVE-2021-26901, CVE-2021-27077)

- An memory corruption vulnerability exists. An attacker can exploit this to corrupt the memory and cause unexpected behaviors within the system/application. (CVE-2021-26411)

- A denial of service (DoS) vulnerability. An attacker can exploit this issue to cause the affected component to deny system or application services. (CVE-2021-26896, CVE-2021-27063)

Solution

Apply Security Only update KB5000851 or Cumulative Update KB5000841.

Public Exploits

Target Network Port(s): 139, 445
Target Asset(s): Host/patch_management_checks
Exploit Available: True (GitHub)
Exploit Ease: Exploits are available

Here's the list of publicly known exploits and PoCs for verifying the KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update vulnerability:

GitHub: https://github.com/CrackerCat/CVE-2021-26411
[CVE-2021-26411]
GitHub: https://github.com/EdgeSecurityTeam/Vulnerability
[CVE-2021-26411]
GitHub: https://github.com/KAB8345/CVE-2021-26411
[CVE-2021-26411]
GitHub: https://github.com/songjianyang/CVE-2021-26882
[CVE-2021-26882: PoC]
GitHub: https://github.com/api0cradle/CVE-2021-26882
[CVE-2021-26882: PoC]

Before running any exploit against any system, make sure you are authorized by the owner of the target system(s) to perform such activity. In any other case, this would be considered as an illegal activity.

WARNING: Beware of using unverified exploits from sources such as GitHub or Exploit-DB. These exploits and PoCs could contain malware. For more information, see how to use exploits safely.

Risk Information

CVSS Score Source [?]: CVE-2021-26861
CVSS V2 Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C/E:H/RL:OF/RC:C

CVSS Base Score:	10.0 (High)
Impact Subscore:	10.0
Exploitability Subscore:	10.0
CVSS Temporal Score:	8.7 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	8.7 (High)

CVSS V3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C

CVSS Base Score:	9.8 (Critical)
Impact Subscore:	5.9
Exploitability Subscore:	3.9
CVSS Temporal Score:	9.4 (Critical)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	9.4 (Critical)

STIG Severity [?]: I
STIG Risk Rating: High

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Plugin Source

#
# (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(147231);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/11/30");

  script_cve_id(
    "CVE-2021-1640",
    "CVE-2021-24107",
    "CVE-2021-26411",
    "CVE-2021-26861",
    "CVE-2021-26862",
    "CVE-2021-26869",
    "CVE-2021-26872",
    "CVE-2021-26873",
    "CVE-2021-26875",
    "CVE-2021-26877",
    "CVE-2021-26878",
    "CVE-2021-26881",
    "CVE-2021-26882",
    "CVE-2021-26893",
    "CVE-2021-26894",
    "CVE-2021-26895",
    "CVE-2021-26896",
    "CVE-2021-26897",
    "CVE-2021-26898",
    "CVE-2021-26899",
    "CVE-2021-26901",
    "CVE-2021-27063",
    "CVE-2021-27077"
  );
  script_xref(name:"MSKB", value:"5000841");
  script_xref(name:"MSFT", value:"MS21-5000841");
  script_xref(name:"MSKB", value:"5000851");
  script_xref(name:"MSFT", value:"MS21-5000851");
  script_xref(name:"IAVA", value:"2021-A-0130-S");
  script_xref(name:"IAVA", value:"2021-A-0134-S");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2021/11/17");

  script_name(english:"KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The remote Windows host is missing security update 5000851
or cumulative update 5000841. It is, therefore, affected by
multiple vulnerabilities :

  - A remote code execution vulnerability. An attacker can
    exploit this to bypass authentication and execute
    unauthorized arbitrary commands. (CVE-2021-26861,
    CVE-2021-26877, CVE-2021-26881, CVE-2021-26893,
    CVE-2021-26894, CVE-2021-26895, CVE-2021-26897)

  - An information disclosure vulnerability. An attacker can
    exploit this to disclose potentially sensitive
    information. (CVE-2021-24107, CVE-2021-26869)

  - An elevation of privilege vulnerability. An attacker can
    exploit this to gain elevated privileges.
    (CVE-2021-1640, CVE-2021-26862, CVE-2021-26872,
    CVE-2021-26873, CVE-2021-26875, CVE-2021-26878,
    CVE-2021-26882, CVE-2021-26898, CVE-2021-26899,
    CVE-2021-26901, CVE-2021-27077)

  - An memory corruption vulnerability exists. An attacker
    can exploit this to corrupt the memory and cause
    unexpected behaviors within the system/application.
    (CVE-2021-26411)

  - A denial of service (DoS) vulnerability. An attacker can
    exploit this issue to cause the affected component to
    deny system or application services. (CVE-2021-26896,
    CVE-2021-27063)");
  # https://support.microsoft.com/en-us/topic/march-9-2021-kb5000851-security-only-update-9e198918-a6d6-46d3-8cfb-bd2b1e2ecb99
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7cce9359");
  # https://support.microsoft.com/en-us/topic/march-9-2021-kb5000841-monthly-rollup-3a2cced1-f436-40c3-a8a1-645f86759088
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?8c5851d4");
  script_set_attribute(attribute:"solution", value:
"Apply Security Only update KB5000851 or Cumulative Update KB5000841.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-26861");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/03/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2021/03/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2021/03/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("smb_check_rollup.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');

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

bulletin = 'MS21-03';
kbs = make_list(
  '5000841',
  '5000851'
);

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');
get_kb_item_or_exit('SMB/WindowsVersion', exit_code:1);

if (hotfix_check_sp_range(win7:'1') <= 0) audit(AUDIT_OS_SP_NOT_VULN);

share = hotfix_get_systemdrive(as_share:TRUE, exit_on_fail:TRUE);
if (!is_accessible_share(share:share)) audit(AUDIT_SHARE_FAIL, share);

if (
  smb_check_rollup(os:'6.1', 
                   sp:1,
                   rollup_date:'03_2021',
                   bulletin:bulletin,
                   rollup_kb_list:[5000841, 5000851])
)
{
  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, hotfix_get_audit_report());
}

The latest version of this script can be found in these locations depending on your platform:

Linux / Unix:
/opt/nessus/lib/nessus/plugins/smb_nt_ms21_mar_5000841.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\smb_nt_ms21_mar_5000841.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/smb_nt_ms21_mar_5000841.nasl

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How to Run

Here is how to run the KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update as a standalone plugin via the Nessus web user interface (https://localhost:8834/):

Click to start a New Scan.
Select Advanced Scan.
Navigate to the Plugins tab.
On the top right corner click to Disable All plugins.
On the left side table select Windows : Microsoft Bulletins plugin family.
On the right side table select KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update plugin ID 147231.
Specify the target on the Settings tab and click to Save the scan.
Run the scan.

Here are a few examples of how to run the plugin in the command line. Note that the examples below demonstrate the usage on the Linux / Unix platform.

Basic usage:

/opt/nessus/bin/nasl smb_nt_ms21_mar_5000841.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a smb_nt_ms21_mar_5000841.nasl -t <IP/HOST>

Run the plugin with trace script execution written to the console (useful for debugging):

/opt/nessus/bin/nasl -T - smb_nt_ms21_mar_5000841.nasl -t <IP/HOST>

Run the plugin with using a state file for the target and updating it (useful for running multiple plugins on the target):

/opt/nessus/bin/nasl -K /tmp/state smb_nt_ms21_mar_5000841.nasl -t <IP/HOST>

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References

MSKB | Microsoft Knowledge Base:

5000841, 5000851

MSFT | Microsoft Security Bulletin:

MS21-5000841, MS21-5000851

IAVA | Information Assurance Vulnerability Alert:

2021-A-0130-S, 2021-A-0134-S

See also:

Similar and related Nessus plugins:

147226 - KB5000802: Windows Security Update (March 2021)
147222 - KB5000803: Windows Security Update (March 2021)
147230 - KB5000807: Windows 10 March 2021 Security Update
147220 - KB5000808: Windows 10 Version 1909 March 2021 Security Update
147224 - KB5000809: Windows 10 Version 1803 March 2021 Security Update
147223 - KB5000822: Windows 10 Version 1809 and Windows Server 2019 March 2021 Security Update
147217 - KB5000856: Windows Server 2008 March 2021 Security Update
147221 - KB5000840: Windows Server 2012 March 2021 Security Update
147229 - KB5000853: Windows 8.1 and Windows Server 2012 R2 March 2021 Security Update
147228 - Security Updates for Internet Explorer (March 2021)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file smb_nt_ms21_mar_5000841.nasl version 1.8. For more plugins, visit the Nessus Plugin Library.

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KB5000851: Windows 7 and Windows Server 2008 R2 March 2021 Security Update - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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