By default, IIS is installed with 2 weak SSL 2.0 ciphersuites that are enabled: SSL2_RC4_128_WITH_MD5 andSSL2_DES_192_EDE3_CBC_WITH_MD5. This can impact the securityof AppScan Enterprise, and the cipher suites should be disabled.
Before you begin
Incorrectly editing the registry may severely damageyoursystem. Before making changes to the registry, you should back upany valued data on your computer.Procedure
- Open theRegistry Editor (Start > Run > regedit).
- Inthe HKEY_LOCAL_MAC HINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Ciphers directory:
- Create a new key called RC4 128/128 (Ciphers > New > KeyRC4 128/128).
- Right-click the key's name and create a new DWORD (32-bit)Value called 'Enabled'. (New > DWORD (32-bit) Value > Enabled).
- Leave the default valueas '0'.
- In the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes directory:
- Create a key called MD5 (Hashes > New > Key > MD5).
- Right-clickthe key's name and create a new DWORD (32-bit)Value called 'Enabled'. (New > DWORD (32-bit) Value > Enabled).
- Leave the default valueas '0'.
- Close the RegistryEditor.
FAQs
How to Disable Weak SSL Cipher Suites
- Introduction.
- About SSL Cipher Suites.
- Backup your ssl.conf.
- Edit the ssl.conf and remove weak ciphers.
- Ensure your changes persist.
- Check and reload Nginx.
- Retesting.
Disable all known weak, discouraged, and deprecated ciphers, to include at least DES, 3DES, RC2, RC4, and NULL ciphers in favour of more secure algorithms such as AES and ChaCha20. Consider disabling cipher suites that use algorithms that are not widely supported, such as IDEA, ARIA, and SEED.
What is the tool to disable cipher suites? ›
The Disable-TlsCipherSuite cmdlet disables a cipher suite. This cmdlet removes the cipher suite from the list of Transport Layer Security (TLS) protocol cipher suites for the computer.
What is the impact of removing weak ciphers? ›
If there are none then the SSL connection fails. So if you are using ciphers that are not supported prior to TLS 1.2 then no client using a lesser version will have any ciphers the server allows. Therefore there is no benefit in supporting the earlier protocols.
How to check weak ciphers? ›
You can use the sslyze option to test any SSL/TLS enabled service on any port. Weak ciphers and known cryptographic vulnerabilities such as the famous Heartbleed are all tested. As are other SSL/TLS attacks from recent years including BEAST, CRIME, BREACH, DROWN, FREAK and POODLE.
What are weak cipher suites? ›
Weak cipher suites enabled. The server supports weak cipher suites for SSL/TLS connections. These cipher suites are currently considered broken and, depending on the specific cipher suite, offer poor or no security at all. Thus defeating the purpose of using a secure communication channel in the first place.
How do I know if cipher suite is enabled? ›
Find the cipher using Chrome
- Launch Chrome.
- Enter the URL you wish to check in the browser.
- Click on the ellipsis located on the top-right in the browser.
- Select More tools > Developer tools > Security.
- Look for the line "Connection...". This will describe the version of TLS or SSL used.
A cipher suite is identified as obsolete when one or more of the mechanisms is weak. Especially weak encryption algorithms in TLS 1.2 are designated as NULL, RC2, RC4, DES, IDEA, and TDES/3DES; cipher suites using these algorithms should not be used9.
How to fix weak SSL TLS key exchange? ›
5 answers
- Click Start, click Run, type regedit in the Open box, and then click OK.
- Locate and then click the following subkey: *HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms*
- On the Edit menu, point to New, and then click Key.
How to Remove CBC Ciphers
- Group Policy. Create new or edit existing GPO. ...
- PowerShell. The command Disable-TlsCipherSuite can be used to remove specific CBC ciphers. ...
- IISCRYPTO. Manually uncheck the CBC ciphers which you want to remove and click Apply.
- Modify registry keys (not advised)
AES based ciphers are more secure than the corresponding 3DES, DES, and RC4 based ciphers. AES-GCM ciphers are more secure than AES-CBC ciphers.
How to disable weak ciphers in IIS? ›
Normally to disable weak ciphers on a Windows server you just run IISCrypto and disable the protocols that you don't want. Reboot the machine and they are no longer available.
How do I disable weak ciphers in SSL? ›
Open the jetty-config-plugin. properties file in your preferred text editor and append the list of ciphers to exclude. Save the file. Restart the PaperCut Application Server service and re-test with an appropriate security scanning tool.
What happens if we disable RC4? ›
In this manner, any server or client that is talking to a client or server that must use RC4 can prevent a connection from occurring. Clients that deploy this setting will be unable to connect to sites that require RC4, and servers that deploy this setting will be unable to service clients that must use RC4.
How to disable weak ciphers in AWS? ›
Ensure weak ciphers are removed for AWS Elastic Load Balancers (...
- Sign in to the AWS Console and go to the EC2 dashboard.
- In the navigation panel, select Load Balancers under Load balancing.
- Select the Elastic Load Balancer.
- Select the Listeners tab. ...
- Find and remove all the insecure cipher definitions.
How to Remove CBC Ciphers
- Group Policy. Create new or edit existing GPO. ...
- PowerShell. The command Disable-TlsCipherSuite can be used to remove specific CBC ciphers. ...
- IISCRYPTO. Manually uncheck the CBC ciphers which you want to remove and click Apply.
- Modify registry keys (not advised)
Disabling Weak Cipher Suites Globally Through Java
- At a command prompt, access the java.security file: ...
- Open the java.security file and locate the following parameter: ...
- In this line, after =SSLv3 , add DES and DESede so that the line looks like this: ...
- Verify that weak cipher suites have been disabled.
