25 October 2016
During the ‘Move Laterally’ phase of a cyber-attack the Pass-the-Hash (PtH) method is often used to jump from one system to another in Windows networks. The best way to deal with PtH attacks is to use only locally defined privileged accounts with individual passwords because the related hashes are not valid on other systems. For more details please see the NSA IAD guideline ‘Reducing the effectiveness of Pass-the-Hash‘.
Using individual passwords on thousands of Windows systems is a really big challenge. In addition, since network login with local users has to be deactivated, the effort for the administrators is significantly increased. With this, the NSA suggestions will, if at all, only be implemented in very few organization.
Today, I participated in a great presentation of BeyondTrust’s Enterprise Password Management solution. Although primarily designed for privileged account management, the solution provides all the capabilities for the efficient management of local privileged accounts, and even with one-time passwords and automated creation of rdp sessions to the target systems. With this, PtH attacks can be mitigated nearly without any extra effort for the administrators.
Have a good day.
16 January 2015
I had some discussions in the past weeks about technical accounts in the administrators group. To be honest, I am a strong supporter of the ZERO administrators doctrine: Under normal conditions the administrators group of a computer has no members. If required, an account is added to the group and removed directly after the job is done. Strict implementation of a ZERO admin doctrine requires the implementation of a smart PAM solution to avoid undue delays in the case of trouble.
What really worries me is that technical accounts are always seen as privileged accounts. And that they are very often assigned to the administrators group for convenience, even though a system login is not required.
For example a technical account for querying a database needs no system privileges at all. Even a login to the application or database server is very often not required. In the best case the technical account only needs the privilege to open a database connection and to get access to a well-known set of database objects. Granting whatever system privileges to such accounts or assigning them to the administrators group enlarges only the attack surface of the system.
As always, the Principle of Least Privilege shows the direction. Grant privileges only if required, carefully evaluate if membership in the administrators group is necessary, and treat membership in the administrators group as an exception. To keep the attack surface small it’s wise to check the administrative groups for unnecessary technical accounts regularly.
Have a good weekend.