By accident, I found a heartbeat/ VLAN issue on a NetScaler cluster at one of my customers. The NetScaler ADC appliances have three interfaces connected to a switch stack. Two of the three interfaces were configured as a channel (LAG). This is a snippet from the config:
set channel LA/1 -tagall ON -throughput 0 -lrMinThroughput 0 -bandwidthHigh 0 -bandwidthNormal 0
… Read more
In 2014, Microsoft announced the Azure Preview Portal, which was going GA in December 2015. Since January 8, 2018, the classic Azure Portal is turned off. The “Preview Portal” was more than a facelift. The classic Azure Portal was based on the Service Management mode, often called the “classic deployment model”, whereas the new Azure Portal uses the Resource Manager model. Azure Service Management (ASM) and Azure Resource Management are both deployment models. The Resource Manager model eases the deployment of complex setups by using templates to deploy, update and manage resources within a resource group as a single operation.… Read more
The Informationsverbund Berlin-Bonn (IVBB), the secure network of the german government , was breached by an unknown hacker group. Okay, a secure government network might be a worthy target for an attack, but your network not, right? Do you use the same password for multiple accounts? There were multiple massive data breaches in the past. Have you ever checked if your data were also compromised? I can recommend haveibeenpwned.com. If you want to have some fun, scan GitHub for -----BEGIN RSA PRIVATE KEY-----. Do you use a full disk encryption on your laptop or PC? Do you sign and/ or encrypt emails using S/MIME or PGP?… Read more
A customer of mine got an appliance from a software vendor. The appliance was delivered as ZIP file with a VMDK, a MF, and an OVF file. Unfortunately, the appliance was created with VMware Workstation 6.0 with virtual machine hardware version 6, which is incompatible with VMware ESXi (Virtual machine hardware versions). During deployment, my customer got this error:
unsupported hardware family 'vmx-06'
The OVF file includes a line with the VM hardware version.
If you change this line from vmx-06 to vmx-07, the hash of the OVF changes, and you will get an error during the deployment of the appliance because of the wrong file hash.… Read more
Some days ago, I have implemented one-time passwords (OTP) for NetScaler Gateway for one of my customers. This feature was added with NetScaler 12, and it’s a great way to secure NetScaler Gateway with a native NetScaler feature. Native OTP does not need any third party servers. But you need a NetScaler Enterprise license, because nFactor Authentication is a requirement.
To setup NetScaler native OTP, I followed the availbe guides on the internet.
The setup is pretty straightforward.… Read more
On January 18, 2018, Microsoft has published KB4074871 which has the title “Exchange Server guidance to protect against speculative execution side-channel vulnerabilities”. As you might guess, Exchange is affected by Meltdown & Spectre – like any other software. Microsoft explains in KB4074871:
Because these are hardware-level attacks that target x64-based and x86-based processor systems, all supported versions of Microsoft Exchange Server are affected by this issue.
Like Citrix, Microsoft does not offer any updates to address this issue, because there is nothing to fix in Microsoft Exchange.… Read more
In addition to my shortcut blog post about Meltdown and Spectre with regard of Microsoft Windows, VMware ESXi and vCenter, and HPE ProLiant, I would like to add some additional information about HPE Storage and Citrix NetScaler.
When we talk about Meltdown and Spectre, we are talking about three different vulnerabilities:
- CVE-2017-5715 (branch target injection)
- CVE-2017-5753 (bounds check bypass)
- CVE-2017-5754 (rogue data cache load)
CVE-2017-5715 and CVE-2017-5753 are known as “Spectre”, CVE-2017-5754 is known as “Meltdown”. If you want to read more about these vulnerabilities, please visit meltdownattack.com.… Read more
I will try to update this blog post regularly!
01-13-2018: Added information regarding VMSA-2018-0004
01-13-2018: HPE has pulled Gen8 and Gen9 system ROMs
01-13-2018: VMware has updated KB52345 due to issues with Intel microcode updates
01-18-2018: Updated VMware section
01-24-2018: Updated HPE section
01-28-2018: Updated Windows Client and Server section
02-08-2018: Updated VMware and HPE section
02-20-2018: Updated HPE section
04-17-2018: Updated HPE section
Many blog posts have been written about the two biggest security vulnerabilities discovered so far.… Read more
Each of us has his or her personal tool chain. Depending on your job role, the tool chain will look different. My personal tool chain does not have changed much over the last few years, but if I added or removed a tool to my tool chain, this change was often influenced by other peoples tool chain.
My primary work device is a Lenovo ThinkPad X250 (Intel i5 5200U, 8 GB RAM, 250 GB SSD) with Windows 10. I’ve added a 6 cell battery, so I have ~ 95 Wh of battery capacity. This gives me ~ 16h of battery lifetime with my common workload. The 12,5″ screen seems to be small, but it’s okay as I have two 24″ displays at the office.… Read more
Exchange has known the concept of internal and external URLs for the different services (Outlook Web Access, OAB, EWS, ActiveSync etc) since Exchange 2007. And it’s still confusing people. The internal URL is the URL, that is used to access the desired service from the intranet. The external URL represents the URL that is used to access the service from the internet. Best practice is to use the same URL (the external) for both, use a certificate from a public CA, and use split DNS to access the external domain from the inside of your network.
People tend to imply, that URLs are not case-sensitive. This seems to be true in most cases.… Read more