Vulnerabilities > CVE-2017-11940 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Microsoft Malware Protection Engine 1.1.10600.0/1.1.10701.0/1.1.14306.0

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

The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on Windows 7 SP1, Windows 8.1, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, 1709 and Windows Server 2016, Windows Server, version 1709, Microsoft Exchange Server 2013 and 2016, does not properly scan a specially crafted file leading to remote code execution. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability". This is different than CVE-2017-11937.

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
NASL idMICROSOFT_MPENG_1_1_14405_2.NASL
descriptionThe version of Microsoft Malware Protection Engine (MMPE) installed on the remote Windows host is prior to 1.1.14405.2. It is, therefore, affected by a remote code execution vulnerability. Note that Nessus has checked if a vulnerable version of MMPE is being used by any of the following applications : - Microsoft Forefront Endpoint Protection 2010 - Microsoft Forefront Endpoint Protection - Microsoft Exchange Server 2013 and 2016 - Microsoft Endpoint Protection - Microsoft Security Essentials - Windows Defender for Windows 7, Windows 8.1, Windows 10, Windows 10 1511, Windows 10 1607, Windows 10 1703, Windows 10 1709, and Windows Server 2016(SC) - Windows Intune Endpoint Protection Also note: Systems running supported versions of Windows Server 2008 R2 are not affected if the Desktop Experience feature is not installed.
last seen2020-06-01
modified2020-06-02
plugin id105109
published2017-12-08
reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/105109
titleMicrosoft Malware Protection Engine < 1.1.14405.2 RCE
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(105109);
  script_version("1.9");
  script_cvs_date("Date: 2019/11/12");

  script_cve_id("CVE-2017-11937", "CVE-2017-11940");
  script_bugtraq_id(102070, 102104);

  script_name(english:"Microsoft Malware Protection Engine < 1.1.14405.2 RCE");
  script_summary(english:"Checks the engine version.");

  script_set_attribute(attribute:"synopsis", value:
"An antimalware application installed on the remote host is affected by
a remote code execution vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Microsoft Malware Protection Engine (MMPE) installed 
on the remote Windows host is prior to 1.1.14405.2. It is, therefore,
affected by a remote code execution vulnerability.

Note that Nessus has checked if a vulnerable version of MMPE is being
used by any of the following applications :

  - Microsoft Forefront Endpoint Protection 2010

  - Microsoft Forefront Endpoint Protection

  - Microsoft Exchange Server 2013 and 2016

  - Microsoft Endpoint Protection

  - Microsoft Security Essentials

  - Windows Defender for Windows 7, Windows 8.1, 
    Windows 10, Windows 10 1511, Windows 10 1607,
    Windows 10 1703, Windows 10 1709, and Windows Server 2016(SC)

  - Windows Intune Endpoint Protection

Also note: Systems running supported versions of Windows Server 2008 
R2 are not affected if the Desktop Experience feature is not installed.");
  # https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-11937
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dd2497a7");
  # https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-11940
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2d42ad9f");
  script_set_attribute(attribute:"solution", value:
"Enable automatic updates to update the scan engine for the relevant
antimalware applications. Refer to Knowledge Base Article 2510781 for
information on how to verify that MMPE has been updated.");
  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:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2017-11940");

  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:"2017/12/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/12/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/08");

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

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

  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("smb_hotfixes.nasl", "fcs_installed.nasl");
  script_require_keys("SMB/Registry/Enumerated");
  script_require_ports(139, 445);

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("smb_func.inc");

get_kb_item_or_exit("SMB/Registry/Enumerated");

# indicates if any antimalware products were found. this is used
# to determine whether or not the plugin should check if defender is affected
antimalware_installed = FALSE;

# Connect to the appropriate share.
port    =  kb_smb_transport();
login   =  kb_smb_login();
pass    =  kb_smb_password();
domain  =  kb_smb_domain();

if(! smb_session_init()) audit(AUDIT_FN_FAIL, 'smb_session_init');

rc = NetUseAdd(login:login, password:pass, domain:domain, share:"IPC$");
if (rc != 1)
{
  NetUseDel();
  audit(AUDIT_SHARE_FAIL, "IPC$");
}

# Connect to remote registry.
hklm = RegConnectRegistry(hkey:HKEY_LOCAL_MACHINE);
if (isnull(hklm))
{
  NetUseDel();
  audit(AUDIT_REG_FAIL);
}

# Figure out where it is installed.
path = NULL;
info = '';
info2 = '';
engine_version = NULL;

fixed_engine_version = "1.1.14405.2";
last_vulnerable = "1.1.14306.0";

# Forefront Client Security (either both or neither of these will be in the KB)
engine_version = get_kb_item("Antivirus/Forefront_Client_Security/engine_version");
fcs_path = get_kb_item("Antivirus/Forefront_Client_Security/path");
if (!isnull(engine_version))
{
  antimalware_installed = TRUE;

  if (ver_compare(ver:engine_version, fix:last_vulnerable) <= 0)
  {
    info +=
      '\n  Product           : Microsoft Forefront Client Security'+
      '\n  Path              : ' + fcs_path +
      '\n  Installed version : ' + engine_version +
      '\n  Fixed version     : ' + fixed_engine_version + '\n';
  }
  else info2 += 'Microsoft Forefront Client Security with MMPE version '+ engine_version + ". ";
}

# Microsoft Security Essentials
# Forefront Endpoint Protection
# System Center Endpoint Protection
engine_version = NULL;

NetUseDel(close:FALSE);
rc = NetUseAdd(login:login, password:pass, domain:domain, share:"IPC$");
if (rc != 1)
{
  NetUseDel();
  audit(AUDIT_SHARE_FAIL, "IPC$");
}

# Connect to remote registry again.
hklm = RegConnectRegistry(hkey:HKEY_LOCAL_MACHINE);
if (isnull(hklm))
{
  NetUseDel();
  audit(AUDIT_REG_FAIL);
}

key = "SOFTWARE\Microsoft\Microsoft Antimalware\Signature Updates";
key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
if (!isnull(key_h))
{
  value = RegQueryValue(handle:key_h, item:"EngineVersion");
  if (!isnull(value)) engine_version = value[1];

  RegCloseKey(handle:key_h);
}

path = NULL;
key = "SOFTWARE\Microsoft\Microsoft Antimalware";
key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
if (!isnull(key_h))
{
  value = RegQueryValue(handle:key_h, item:"InstallLocation");
  if (!isnull(value)) path = value[1];

  RegCloseKey(handle:key_h);
}

if(!isnull(path))
{
  found = 0;
  # Check if the main exe exists.
  share = ereg_replace(pattern:"^([A-Za-z]):.*", replace:"\1$", string:path);
  exe =  ereg_replace(pattern:"^[A-Za-z]:(.*)", replace:"\1\MsMpEng.exe", string:path);
  NetUseDel(close:FALSE);
  rc = NetUseAdd(login:login, password:pass, domain:domain, share:share);
  if (rc != 1)
  {
    NetUseDel();
    audit(AUDIT_SHARE_FAIL, share);
  }
  fh = CreateFile(
    file:exe,
    desired_access:GENERIC_READ,
    file_attributes:FILE_ATTRIBUTE_NORMAL,
    share_mode:FILE_SHARE_READ,
    create_disposition:OPEN_EXISTING
  );
  if (!isnull(fh))
  {
    antimalware_installed = TRUE;
    found = 1;
    CloseFile(handle:fh);
  }

  if (found && !isnull(engine_version))
  {
    if (ver_compare(ver:engine_version, fix:last_vulnerable) <= 0)
    {
      info +=
       '\n  Product           : Microsoft Security Essentials / Forefront Endpoint Protection / System Center Endpoint Protection'+
       '\n  Path              : ' + share[0] + ':' + exe +
       '\n  Installed version : ' + engine_version +
       '\n  Fixed version     : ' + fixed_engine_version + '\n';
    }
    else info2 += 'Microsoft Security Essentials / Forefront Endpoint Protection / System Center Endpoint Protection with MMPE version ' + engine_version + ". ";
  }
}

# Microsoft Windows Defender
# defender is apparently disabled when other antimalware products are installed,
# so it will only be checked if the plugin hasn't detected other products are present
if (!antimalware_installed)
{
  defender_enabled = TRUE;
  engine_version = NULL;

  # Check if Windows Defender is disabled via group policy
  key = "SOFTWARE\Policies\Microsoft\Windows Defender";
  key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
  if (!isnull(key_h))
  {
    value = RegQueryValue(handle:key_h, item:"DisableAntiSpyware");
    if (!isnull(value))
    {
      if (value[1] > 0)
      {
        defender_enabled = FALSE;
      }
    }
    RegCloseKey(handle:key_h);
  }
  key = "SOFTWARE\Microsoft\Windows Defender";
  key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
  if (!isnull(key_h))
  {
    value = RegQueryValue(handle:key_h, item:"DisableAntiSpyware");
    if (!isnull(value))
    {
      if (value[1] > 0)
      {
        defender_enabled = FALSE;
      }
    }
    RegCloseKey(handle:key_h);
  }
  if (defender_enabled)
  {
    key = "SOFTWARE\Microsoft\Windows Defender\Signature Updates";
    key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
    if (!isnull(key_h))
    {
      value = RegQueryValue(handle:key_h, item:"EngineVersion");
      if (!isnull(value)) engine_version = value[1];

      RegCloseKey(handle:key_h);
    }

    path = NULL;
    key = "SOFTWARE\Microsoft\Windows Defender\Signature Updates";
    key_h = RegOpenKey(handle:hklm, key:key, mode:MAXIMUM_ALLOWED);
    if (!isnull(key_h))
    {
      value = RegQueryValue(handle:key_h, item:"SignatureLocation");
      if (!isnull(value)) path = value[1];

      RegCloseKey(handle:key_h);
    }

    if(!isnull(path))
    {
      found = 0;
      defender_dll = NULL;
      # Check the version of the main exe.
      share = ereg_replace(pattern:"^([A-Za-z]):.*", replace:"\1$", string:path);
      # this is the path smb_kb4022344.nasl checks
      dll1 =  ereg_replace(pattern:"^[A-Za-z]:(.+Windows Defender\\Definition Updates).+", replace:"\1\Default\MpEngine.dll", string:path);
      # this path works for Windows Defender on Windows 8
      dll2 =  ereg_replace(pattern:"^[A-Za-z]:(.+)$", replace:"\1\MpEngine.dll", string:path);
      NetUseDel(close:FALSE);
      rc = NetUseAdd(login:login, password:pass, domain:domain, share:share);
      if (rc != 1)
      {
        NetUseDel();
        audit(AUDIT_SHARE_FAIL, share);
      }
      fh = CreateFile(
        file:dll1,
        desired_access:GENERIC_READ,
        file_attributes:FILE_ATTRIBUTE_NORMAL,
        share_mode:FILE_SHARE_READ,
        create_disposition:OPEN_EXISTING
      );
      if (!isnull(fh))
      {
        found =1 ;
        defender_dll = share[0] + ':' + dll1;
        CloseFile(handle:fh);
      }

      if (found == 0)
      {
        fh = CreateFile(
          file:dll2,
          desired_access:GENERIC_READ,
          file_attributes:FILE_ATTRIBUTE_NORMAL,
          share_mode:FILE_SHARE_READ,
          create_disposition:OPEN_EXISTING
        );
        if (!isnull(fh))
        {
          found =1 ;
          defender_dll = share[0] + ':' + dll2;
          CloseFile(handle:fh);
        }
      }

      if (found && !isnull(engine_version))
      {
        if (ver_compare(ver:engine_version, fix:last_vulnerable) <= 0)
        {
          info +=
           '\n  Product           : Microsoft Windows Defender'+
           '\n  Path              : ' + defender_dll +
           '\n  Installed version : ' + engine_version +
           '\n  Fixed version     : ' + fixed_engine_version + '\n';
        }
        else info2 += 'Microsoft Windows Defender with MMPE version ' + engine_version + ". ";
      }
    }
  }
}

RegCloseKey(handle:hklm);
NetUseDel();

if (info)
{
  report = '\n' +
    "Nessus found following vulnerable product(s) installed :" +'\n'+
    info;
  security_report_v4(severity:SECURITY_HOLE, port:port, extra:report);

  exit(0);
}
else if(info2) exit(0,"The following instance(s) of MMPE are installed and not vulnerable : "+ info2);
else exit(0, "Nessus could not find evidence of affected Microsoft antimalware products installed.");