Stuff I'm Up To

Technical Ramblings

Netsh Commands for NPS — April 3, 2017
CVE – Security Vunerability Datasource — March 18, 2017
STIG — March 17, 2017
Oracle Database Patches —
Guidelines for Microsoft Clustering on vSphere — March 9, 2017

Guidelines for Microsoft Clustering on vSphere

This article provides links to a subset of articles that provide guidelines and support status for running various Microsoft clustering solutions and configurations on VMware vSphere.

VMware provides customers additional flexibility and choice in architecting high-availability solutions. Microsoft has clear support statements for its clustering solutions on VMware.

Additionally, VMware provides guidelines in terms of storage protocols and number of nodes supported by VMware on vSphere, particularly for specific clustering solutions that access shared storage. Other clustering solutions that do not access shared storage, such as Exchange Cluster Continuous Replication (CCR) and Database Availability Group (DAG), can be implemented on VMware vSphere just like on physical systems without any additional considerations.

https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1037959

Setting the Killbit for an ActiveX Control — March 7, 2017

Setting the Killbit for an ActiveX Control

Adding a killbit for a control that Nessus says requires one.

https://support.microsoft.com/en-gb/help/240797/how-to-stop-an-activex-control-from-running-in-internet-explorer

In brief you need to find or create the classid in:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility

However, on one I found I first had to hunt the name in HKEY_CLASSES_ROOT\CLSID

eg. Nessus reported

  Class Identifier  : {D63891F1-E026-11D3-A6C3-005004055C6C}
  Filename          : C:\Program Files (x86)\xxxx\Runtime\NCSECW.DLL
  Installed version : 1.6.6.32

But when I search for NCSECW.DLL I got a different Class ID and that was what I needed to use to add a killbit for.

Diving Deeper into Windows SSL — March 2, 2017

Diving Deeper into Windows SSL

This response to a question raised some interest and I found it very interesting. I then went to investigate the keys and values on my own machine. This can also be controlled using gpedit.msc, but found it interesting to see the current entries for myself.

HKLM\System\CurrentControlSet\Control\Cryptography\Configuration\Local\SSL\00010002 Functions

While not “incorrect” Steven’s answer is incomplete.

The linked article is a very good description for how to enable and disable cipher suites like SSL 2.0 etc, but SH’s pen test comments posted are also concerned about the mode of operation of the ciphers used – specifically about removing the use of CBC (Cipher Block Chaining) and using Counter (CTR) or Galois Counter (GCM). This is not fully covered in that answer.

In order to direct how the transport security is negotiated in this more granular level, they will also need to look at the content and ordering of the Functions list. This controls the preferred order and what is acceptable when the transport security is negotiated between server/webserver and client/browser.

HKLM\System\CurrentControlSet\Control\Cryptography\Configuration\Local\SSL\00010002  Functions

Removal of CBC modes of operation from the list would prevent their sucesful negociation, but removal of all CBC is likely to have negative impact. Adjusting this list must be done with great care as misconfiguration will prevent sucesful connections. Support for modern modes of block cipher operation such as e.g. AES-GCM are still not completely widespread (March 2016) in all clients/browsers and OS versions.

As with much of crypto, what might be appropriate for state top-secrets and what might be appropriate for information of very low confidentiality won’t always be the same. A balanced approach for information assurance is needed depending on the categorization of the specific information and not an approach like CBC is “bad” GCM is “good”.

S.H. should probably return to his/her pen testers to discuss whether their specific use of CBC modes may be acceptable for a while longer until GCM is better adopted, before testing any adjustements to the Functions list.

Tuesday, March 08, 2016 9:46 AM, Tom Hollinghurst

 

References: https://social.technet.microsoft.com/Forums/windowsserver/en-US/a51f9574-73b0-4808-ad5f-4db081d80e6f/disable-cbc-mode-cipher-encryption-and-enable-ctr-or-gcm-cipher-mode-encryption-disable-md5-and?forum=winserversecurity

IIS HTTP to HTTPS — March 1, 2017

IIS HTTP to HTTPS

In the process of deploying an IIS web server we’d like to ensure that browsers that visit the http unencrypted page, get redirected to the https encrypted page.

By default IIS comes with a “HTTP Redirect” module but this doesn’t really do what we’re after. HTTP Redirect simply takes any request and forwards it to a specific URL. So it doesn’t care about the original host name header, URI or query string that was supplied by the browser, it just takes you to the exact URL that you specify.

To get the behaviour we’re expecting we need to install another module called “URL Rewrite”

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OpenSSL Ciphers —

OpenSSL Ciphers

OpenSSL is a very handy tool. Both on Linux and Windows. On both you can do all kinds of conversions and creations,  but equally of use you can view cipher details that are supported.

On Linux systems OpenSSL will look for /usr/local/ssl/openssl.cnf, or on some flavours /etc/ssl/openssl.cnf or even /usr/lib/ssl/openssl.cnf and on windows it will show a warning.

WARNING: can't open config file: /usr/local/ssl/openssl.cnf

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SSL/TLS as a Server Admin — February 28, 2017

SSL/TLS as a Server Admin

I’m not an encryption expert by any means. I’ve no great understanding of the mathematics involved in the encryption process and the ciphers used. What I do understand is what that means from the point of view of a server admin.

One thing to state right now is that SSL/TLS are the same thing. SSL was simply renamed TLS, but the underlying principles are the same, the mechanisms and ciphers change, but the concept is the same – and despite the change it’s still mostly referred to as SSL.

The basic process of SSL is that in order to engage in a secure conversation between systems both systems must share a level of trust with a common 3rd party.

I don’t trust you just because we can encrypt data together. I need to trust you based on a 3rd party we both trust telling me that you are who you say you are.

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Updating ADFS Certificates — February 25, 2017

Updating ADFS Certificates

This wasn’t as easy as I thought it was going to be. I expected just to import the new certificate into the mmc certificate snap in and then set ADFS to use it in the ADFS Management console by choosing “Set Service Communication Certificate…”. Why would it need to be more difficult than that?

Turns out it is more difficult than that. I tried a few things to get it going with no success. The service starts up just fine, but the website at https://adfs.domain.tld remains down.

I check out event viewer and sure enough we have some pretty useless errors logged when I try to visit it.

Event ID: 15021, An error occurred while using SSL configuration for endpoint adfs.domain.tld:443.  The error status code is contained within the returned data.

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Horizon SSL/TLS Ciphers —

Horizon SSL/TLS Ciphers

After running an SSL scan on our external facing Horizon Security Server, using Qualys’ SSLTest and receiving an A- rating, I wanted to fix that by getting at least an A. But in order to do that I needed to understand what was required to get it to an A.

The problem I faced was that I was being marked down for not supporting Perfect Forward Secrecy (PFS).

The server does not support Forward Secrecy with the reference browsers. Grade reduced to A-

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