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Disable insecure "MD5" hash

Overview​

About this script

This script improves your privacy on Windows.

These changes use Windows system commands to update your settings.

This script disables the use of the MD5 1 2 3 hash algorithm during the SSL/TLS handshake process.

This script only affects the SSL/TLS handshake process. The SSL/TLS handshake is a key part of establishing a secure connection over the internet. By disabling this weak algorithm, the script improves the security of the connection.

This algorithm is vulnerable to collision attacks 4 5. This vulnerability enables attackers to spoof content, perform phishing, or execute man-in-the-middle attacks 6. Consequently, an attacker could intercept or modify data transmitted over what is believed to be a secure connection, without being detected. For instance, attackers could exploit this to divert your payments to their accounts, creating significant risks.

Authorities like NIST (FIPS) 2, Federal Office for Information Security (BSI) 3, Microsoft 6, OWASP 4 7, Internet Engineering Task Force (IETF) 8, Google 9 10, Firefox 11 and OpenVPN 12 classify this algorithm as weak and recommend against its use.

This algorithm is enabled by default on Windows 2.

Disabling this algorithm disallows the following cipher suites:

  • SSL_CK_DES_192_EDE3_CBC_WITH_MD5 1
  • SSL_CK_DES_64_CBC_WITH_MD5 1
  • SSL_CK_RC4_128_EXPORT40_MD5 1
  • SSL_CK_RC4_128_WITH_MD5 1
  • SSL_RSA_EXPORT_WITH_RC4_40_MD5 2
  • SSL_RSA_WITH_RC4_128_MD5 2
  • SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5 2
  • TLS_RSA_EXPORT_WITH_RC4_40_MD5 1 2
  • TLS_RSA_WITH_NULL_MD5 1
  • TLS_RSA_WITH_RC4_128_MD5 1 2
  • TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5 2
Caution

This may cause compatibility issues with older devices or software.

This script uses Batch (batchfile) scripting language.

Use with Caution

This script is only recommended if you understand its implications. Some non-critical or features may no longer function correctly after running this script.

Implementation Details

  • Language: batch

  • Required Privileges: Administrator rights

  • Compatibility: Windows only

  • Reversibility: Can be undone using provided revert script

Explore Categories​

This action belongs to Disable insecure hashes category. This category includes scripts to disable insecure hash algorithms during cryptographic operations. Hash algorithms are essential for internet security, electronic banking, and document signing. Insecure hashes, however, are susceptible to collision attacks. This vulnerability enables attackers... Read more on category page ▶

Apply now​

Choose one of three ways to apply:

  1. Automatically via privacy.sexy: The easiest and safest option.
  2. Manually by downloading: Requires downloading a file.
  3. Manually by copying: Advanced flexibility.

Alternative 1. Apply with Privacy.sexy​

privacy.sexy is free and open-source application that lets securely apply this action easily.

Open privacy.sexy

You can fully restore this action (revert back to the original behavior) using the application.

privacy.sexy instructions
  1. Open or download the desktop application
  2. Search for the script name: Disable insecure "MD5" hash.
  3. Check the script by clicking on the checkbox.
  4. Click on Run button at the bottom of the page.

Alternative 2. Download​

Irreversible Changes

This script is irreversible, meaning there is no straightforward method to restore changes once applied. Exercise caution before running, restoring it may not be possible.

  1. Download the script file by clicking on the button below:

    Download script

  2. Run the script file by clicking on it.

Download revert script​

This file restores your system to its original state, before this script is applied.

Download restore script

Alternative 3. Copy​

This is for advanced users. Consider automatically applying or downloading the script for simpler way.

  1. Open Command Prompt as administrator.
HELP: Step-by-step guide

  1. Click on Start menu

  2. Type cmd

  3. Right click on Command Prompt select Run as administrator

  4. Click on Yes to run Command Prompt

Animation showing how to open terminal as administrator on Windows 11

  1. Copy the following code:
Code to apply changes
:: Disable usage of "MD5" hash algorithm for TLS/SSL connections
:: Set the registry value: "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5!Enabled"
PowerShell -ExecutionPolicy Unrestricted -Command "$registryPath = 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5'; $data = '0'; reg add 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5' /v 'Enabled' /t 'REG_DWORD' /d "^""$data"^"" /f"
  1. Right click on command prompt to paste it.
  2. Press Enter to apply remaining code.

Copy restore code​

Copy and run the following code to restore changes:

Revert code
:: Restore usage of "MD5" hash algorithm for TLS/SSL connections
:: Delete the registry value "HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5!Enabled"
PowerShell -ExecutionPolicy Unrestricted -Command "reg delete 'HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\MD5' /v 'Enabled' /f 2>$null"

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