Vulnerabilities > CVE-2016-7270 - Cryptographic Issues vulnerability in Microsoft .Net Framework 4.6.2

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
NONE
Availability impact
NONE
network
low complexity
microsoft
CWE-310
nessus

Summary

The Data Provider for SQL Server in Microsoft .NET Framework 4.6.2 mishandles a developer-supplied key, which allows remote attackers to bypass the Always Encrypted protection mechanism and obtain sensitive cleartext information by leveraging key guessability, aka ".NET Information Disclosure Vulnerability."

Vulnerable Configurations

Part Description Count
Application
Microsoft
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Signature Spoofing by Key Recreation
    An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

Msbulletin

bulletin_idMS16-155
bulletin_url
date2016-12-13T00:00:00
impactInformation Disclosure
knowledgebase_id3205640
knowledgebase_url
severityImportant
titleSecurity Update for .NET Framework

Nessus

NASL familyWindows : Microsoft Bulletins
NASL idSMB_NT_MS16-155.NASL
descriptionThe remote Windows host is missing a security update. It is, therefore, affected by an information disclosure vulnerability in the .NET Framework Data Provider for SQL Server due to improper handling of developer-supplied keys. An unauthenticated, remote attacker can exploit this to disclose sensitive information that should be protected by the Always Encrypted feature. Furthermore, an attacker who can access incorrectly encrypted data could decrypt that data by using an easily guessable key. Misuse of the key can also result in access to data being temporarily lost.
last seen2020-05-16
modified2016-12-13
plugin id95772
published2016-12-13
reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/95772
titleMS16-155: Security Update for .NET Framework (3205640)
code
#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(95772);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/05/15");

  script_cve_id("CVE-2016-7270");
  script_bugtraq_id(94741);
  script_xref(name:"MSFT", value:"MS16-155");
  script_xref(name:"MSKB", value:"3204801");
  script_xref(name:"MSKB", value:"3204802");
  script_xref(name:"MSKB", value:"3204805");
  script_xref(name:"MSKB", value:"3205377");
  script_xref(name:"MSKB", value:"3205378");
  script_xref(name:"MSKB", value:"3205379");
  script_xref(name:"MSKB", value:"3206632");
  script_xref(name:"IAVA", value:"2016-A-0349-S");

  script_name(english:"MS16-155: Security Update for .NET Framework (3205640)");
  script_summary(english:"Checks the file versions.");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by an information disclosure
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote Windows host is missing a security update. It is,
therefore, affected by an information disclosure vulnerability in the
.NET Framework Data Provider for SQL Server due to improper handling
of developer-supplied keys. An unauthenticated, remote attacker can
exploit this to disclose sensitive information that should be
protected by the Always Encrypted feature. Furthermore, an attacker
who can access incorrectly encrypted data could decrypt that data by
using an easily guessable key. Misuse of the key can also result in
access to data being temporarily lost.");
  # https://docs.microsoft.com/en-us/security-updates/SecurityBulletins/2016/ms16-155
  script_set_attribute(attribute:"see_also", value:"https://www.nessus.org/u?cb2ef42c");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released a set of patches for Microsoft .NET Framework 4.6.2.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:N");
  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:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/12/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/12/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:.net_framework");
  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) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("smb_hotfixes.nasl", "ms_bulletin_checks_possible.nasl", "microsoft_net_framework_installed.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("misc_func.inc");
include("install_func.inc");

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

global_var bulletin, vuln, arch;

arch = get_kb_item_or_exit('SMB/ARCH');
vuln = 0;
bulletin = 'MS16-155';

kbs = make_list(
  "3204801", # Server 2012 .NET 4.6.2 Security Only
  "3204802", # 8.1 / 2012 R2 .NET 4.6.2 Security Only
  "3204805", # 7 / 2008 R2 .NET 4.6.2 Security Only
  "3205377", # Server 2012 .NET 4.6.2 Monthly Rollup
  "3205378", # 8.1 / 2012 R2 .NET 4.6.2 Monthly Rollup
  "3205379", # 7 / 2008 R2 .NET 4.6.2 Monthly Rollup
  "3206632" # 10 Version 1607 / Server 2016 .NET 4.6.2
);

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

if (hotfix_check_sp_range(vista:'2', win7:'1', win8:'0', win81:'0', win10:'0') <= 0) audit(AUDIT_OS_SP_NOT_VULN);

productname = get_kb_item_or_exit("SMB/ProductName", exit_code:1);
if ("Windows 8" >< productname && "Windows 8.1" >!< productname) audit(AUDIT_OS_SP_NOT_VULN);

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

# dotnet checks
function perform_dotnet_checks()
{
  local_var dotnet_452_installed, dotnet_46_installed, dotnet_461_installed, dotnet_35_installed, dotnet_462_installed;
  local_var ver, missing, count, installs, install;

  # Determine if .NET 4.6.2 is installed
  dotnet_462_installed = FALSE;

  # Make sure to add dependency for microsoft_net_framework_installed.nasl
  count = get_install_count(app_name:'Microsoft .NET Framework');
  if (count > 0)
  {
    installs = get_installs(app_name:'Microsoft .NET Framework');
    foreach install(installs[1])
    {
      ver = install["version"];
      if (ver == "4.6.2") dotnet_462_installed = TRUE;
    }
  }
  # .NET 4.6.2
  if (dotnet_462_installed)
  {
    ############# KB3206632 #############
    # .NET Framework 4.6.2              #
    #  Windows 10 Version 1607          #
    #  Server 2016                      #
    #####################################
    missing = 0;
    missing += hotfix_is_vulnerable(os:"10", sp:0, os_build:"14393", file:"system.data.dll", version:"4.6.1636.0", min_version:"4.6.0.0", dir:"\Microsoft.NET\Framework\v4.0.30319");

    if (missing > 0) hotfix_add_report(bulletin:bulletin, kb:"3206632");
    vuln += missing;

    ########### KB3204801 / KB3205377 ####
    # .NET Framework 4.6.2 Security Only #
    # Windows Server 2012                #
    # KB3204801 Security Only            #
    # KB3205377 Monthly Rollup           #
    ######################################
    missing = 0;
    missing += hotfix_is_vulnerable(os:"6.2", sp:0, file:"system.data.dll", version:"4.6.1636.0", min_version:"4.6.0.0", dir:"\Microsoft.NET\Framework\v4.0.30319");

    if (missing > 0) hotfix_add_report(bulletin:bulletin, kb:"3204801");
    vuln += missing;

    ############ KB3204802 / KB3205378 ###
    # .NET Framework 4.6.2 Security Only #
    # Windows 8.1                        #
    # Windows Server 2012 R2             #
    # KB3204802 Security Only            #
    # KB3205378 Monthly Rollup           #
    ######################################
    missing = 0;
    missing += hotfix_is_vulnerable(os:"6.3", sp:0, file:"system.data.dll", version:"4.6.1636.0", min_version:"4.6.0.0", dir:"\Microsoft.NET\Framework\v4.0.30319");

    if (missing > 0) hotfix_add_report(bulletin:bulletin, kb:"3204802");
    vuln += missing;

    ########### KB3204805 / KB3205379 ####
    # .NET Framework 4.6.2 Security Only #
    # Windows 7 SP1                      #
    # Windows Server 2008 R2 SP1         #
    # KB3204805 Security Only            #
    # KB3205379 Monthly Rollup           #
    ######################################
    missing = 0;
    missing += hotfix_is_vulnerable(os:"6.1", sp:1, file:"system.data.dll", version:"4.6.1636.0", min_version:"4.6.0.0", dir:"\Microsoft.NET\Framework\v4.0.30319");

    if (missing > 0) hotfix_add_report(bulletin:bulletin, kb:"3204805");
    vuln += missing;
  }
}

perform_dotnet_checks();

if(vuln)
{
  set_kb_item(name:'SMB/Missing/'+bulletin, value:TRUE);
  hotfix_security_warning();
  hotfix_check_fversion_end();
  exit(0);
}
else
{
  hotfix_check_fversion_end();
  audit(AUDIT_HOST_NOT, 'affected');
}