Active Directory user objects possess a number of logon metadata attributes that are valuable for Active Directory audit reporting and administration. For example, they are commonly used to identify user accounts that have been inactive for a significant period, or as “stale” accounts. However, each logon metadata attribute has some unique behaviors that need to be understood.
One critical way that attackers gain access to an IT environment and escalate their privileges is by stealing user password hashes and cracking them offline. We covered a method for harvesting service account passwords in our post on Kerberoasting. Here we will explore a technique that works against certain user accounts, AS-REP Roasting. We’ll cover how adversaries perform AS-REP Roasting using the Rubeus tool and how you can defend your organization against these attacks.
Note: The examples in this post use apt commands, which are for Debian-based operating systems like Ubuntu, Kali and Mint. However, the examples have also been tested with yum/dnf commands for RPM-based distros like CentOS, Red Hat, Fedora and openSUSE.
Learning how attackers target weak domain account passwords is not enough for Active Directory security. Let’s look beyond domain accounts and understand the ways adversaries attack local accounts on Windows servers and desktops. For this post, we will focus on the most important local account: Administrator.
I was speaking with an Active Directory security engineer at a global pharmaceutical company recently, and I asked him the most classic question in the product management handbook: “What keeps you up at night?” So cliché (I know), but sometimes instead of an eye roll, you get a real gem, which is exactly what happened.
By default, when you create a new Internet Information Services (IIS) website, it’s open to everyone with anonymous access enabled — anyone can access and view the data being hosted by that site. Obviously, this is a security concern for most organizations. Indeed, I’m often asked by clients and colleagues how to lock down an IIS site so only the desired people can access it.
IT pros are well aware that Active Directory has two types of groups: security groups, which are used to assign permissions to shared resources, and distribution groups, which are used to create email distribution lists. But not everyone understands that each of these Active Directory groups has a scope — and understanding how scope works is vital to security and business continuity. This blog post dives into what group scope is and exactly why it’s important.
Group Policy objects are critical for managing Windows Server infrastructure. To avoid severe service issues, administrators must configure GPOs carefully and be prepared to revert any changes quickly by backing them up before modifying them.
Abusing a gMSA is relatively simple conceptually. First, get its password using a tool like Mimikatz or by querying it directly due to insecure configurations in Active Directory. Since gMSAs are service accounts, they’re usually relatively privileged, so you’ll usually be able to move laterally or escalate. Let’s walk through an example scenario.
Digest Authentication is a challenge/response protocol that was primarily used in Windows Server 2003 for LDAP and web-based authentication. It utilizes Hypertext Transfer Protocol (HTTP) and Simple Authentication Security Layer (SASL) exchanges to authenticate. At a high level, a client requests access to something, the authenticating server challenges the client, and the client responds to the challenge by encrypting its response with a key derived from the password.
