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Potential ESX(i) 4.1 Update 1 upgrade caveat

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If you are planing on upgrading to the recent release of ESX(i) 4.1 Update 1 from ESX(i) 4.1, you may want to verify that you will not be impacted by a previous security/password bug found in ESX(i)4.1. The security bug that was identified with ESX(i) 4.1 was the encryption algorithm which changed from default MD5 as previous releases of ESX(i) to legacy DES.

This bug has since been resolved and a VMware KB article (KB1024500) was released with a temporary fix by adding the keyword "md5" to system-auth PAM configuration entry. This fix also required the user to update the root password afterwards, as the previous password was encrypted using DES.

The potential caveat is if you did not apply the fix as mentioned from the above VMware KB article prior to upgrade, after the ESX(i) 4.1 Update 1 upgrade, you will continue to run into the same problem. The fix is to reset your root password after the upgrade of ESX(i) 4.1 Update 1, this will ensure that the new password will be encrypted using the MD5 algorithm. Though the fix is simple, it can be tedious and manual for users who do not regularly rotate their root passwords or have an automated password management system.

To check whether this will impact your upgrade, login to ESXi Tech Support Mode or classic ESX Service Console and check whether the root password was encrypted using MD5 or DES. To do so, you will cat out the contents of /etc/shadow

If the root password was encrypted using MD5 algorithm, you should see root hash start with "$1$"

If the root password was encrypted using DES algorithm, the root hash will not start with "$1$"

If it is the latter, you will need to either apply the fix and update the root password before upgrading or reset the password after your upgrade. To change the root password, you need to login to either the Serivce Console for ESX or Tech Support Mode for ESXi and run the passwd utility to change your password.

It is probably quicker to rebuild than to login to each host an update the root password, especially if you have an automated kickstart environment. This will ensure that that all hosts will be consistent and no manual fixes will be required. IMHO, this is something that VMware should have clearly pointed out in their release notes as not everyone may be aware of the VMware KB article and implemented the fix prior to upgrade.

Updated vSphere Security Hardening Report Script for vSphere 4.1

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VMware released earlier this week the first draft copy of the vSphere 4.1 Security Hardening Guide which provides several changes to the vSphere 4.0 version released last year. Unfortunately there was no change list provided and you have to manually go through both documents to get the differences. Luckily I did the heavy lifting for you and here are the changes in 4.1 version:

Edit: It looks like Charu of VMware has already posted a "diff" of the 4.0 and 4.1 version here.

Added Checks (14):

  • VSH07 (Enterprise) - Check for privilege re-assignment after vCenter Server restarts
  • VSH10 (Enterprise) - Clean up log files after failed installations of vCenter Server
  • VUM06 (Enterprise) - Do not use default self-signed certificates
  • VMX23 (Enterprise) - Use secure protocols for virtual serial port access
  • VMX24 (DMZ) - Disable certain unexposed features
  • VMX56 (Enteprise) - Restrict access to VMsafe network APIs
  • HIN02 (Enterprise) - Keep ESX/ESXi system properly patched
  • HCM05 (DMZ) - Disable Welcome web page
  • HMT12 (Enterprise) - Prevent unintended use of VMsafe network APIs
  • HMT15 (Enterprise) - Audit for loading of unauthorized kernel modules (ESXi only)
  • HMT20 (DMZ) - Ensure that vpxuser auto-password change meets policy
  • HMT21 (DMZ) - Ensure that vpxuser password meets length policy
  • HCN05 (SSLF) - Disable DCUI to prevent all local administrative control
  • HCN06 (Enterprise) - Disable Tech Support Mode unless needed for diagnostics and break-fix

Removed Checks (10):

  • VMX03 (Enterprise) - Disable copy/paste to remote console
  • VMX51 (Enterprise) - Restrict access to VMsafe CPU/memory APIs
  • VMX54 (Enterprise) - Restrict access to VMsafe network APIs
  • HCM04 (Enterprise) - Ensure that ESX is configured to encrypt all sessions
  • HMT10 (Enterprise) - Prevent unintended use of VMsafe CPU/memory APIs
  • HMT11 (Enterprise) - Prevent unintended use of VMsafe network APIs
  • HCN01 (Enterprise) - Ensure that only authorized users have access to the DCUI
  • HCN03 (Enterprise) - Avoid adding the root user to local groups
  • HCN04 (SSLF) - Disable tech support mode
  • COP06 (DMZ) - Ensure that vpxuser auto-password change in vCenter meets policy

Note: Some of the removed checks may have been replaced with newer and updated information and shows up in the added checks.

To help with your vSphere validation, here is the latest version of the vSphere Security Hardening Report script 1.5 script. There have been a few enhancements to the script which only validates a check based on whether it it is applicable to classic ESX or ESXi, which in the past it would display "N/A". There is also some further validation of the service endpoints for /, /ui, and /mob that may also help reduce manual verification where applicable. You can also join the new vSphere Security Hardening Report VMTN Group for new updates, bug report and discussions.

Here is an updated sample report based on vSphere 4.1:
vmwarevSphereSecurityHardeningReport-SAMPLE.html

One other thing I noticed while going through both the 4.0 and 4.1 security guide is the numbers for the code are all over the place, there are sometimes huge gaps that are unexplained (e.g. VSH6, VSH7 ... VSH10)

How to configure and use vMA's vi-fastpass with fpauth and adauth on vSphere 4.1

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From time to time, I see users posting on the VMTN forums with some questions and confusion around the proper implementation and functionality of vMA's vi-fastpass. The confusion is further enhanced with the new Active Directory functionality and integration with vMA's new vi-fastpass type called adauth.

The vi-fastpass component found in vMA is a credentials caching mechanism to allow you to connect to your ESX(i) or vCenter servers. Prior to vMA 4.1, vMA 4.0 only supported one type of vi-fastpass which is just called fpauth (fastpass authentication). This fpauth basically allows you to manage an ESX(i) or vCenter server under vMA by creating a vi-adminXX and vi-userXX account. The password for these two accounts are obfuscated using a simple XOR cipher. A user can now initialize one of these managed targets and execute either vCLI or vSphere SDK for Perl scripts without having to specify credentials each and every time, this works because the vi-adminXX credentials are being used to connect to your target. This can make running a simple command across n-number of hosts simple without having to provide the credentials for every host.

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