Protecting Active Directory: Strategies to Block Data Exfiltration After Credential Compromise

Question

My organization manages an Active Directory (AD) environment and we're worried about potential information leaks even if attackers acquire valid user credentials. We want to prevent unauthorized tools like ldapdomaindump and similar ones from collecting AD object information even if they compromise a regular user account and gain valid login credentials. What are effective strategies and best practices to implement a layered defense in our AD environment, protecting sensitive data even with stolen user credentials? This could include network restrictions, endpoint security measures, user awareness training, and potentially advanced solutions like DLP or PAM. Our specific areas of interest are:

• Effective network-level controls to block unauthorized LDAP communication attempts.
• Endpoint security recommendations to prevent unauthorized applications from running and exfiltrating data.
• User awareness strategies to minimize the risk of credential compromise through phishing or social engineering.
• Potential advanced solutions like DLP or PAM that could further bolster our defense.

Our AD is implemented in Windows Server 2019 with the latest security patches installed and is not internet-facing. We don't have any AV/EDR available, but our domain firewall is active. We appreciate any insights and expertise from the community on tackling this crucial security challenge and ensuring our AD information's integrity.

Answer 1

Hi @Md. Robayet Ferdous •

I recommend you to be accompanied by an active directory security expert in order to detect vulnerabilities in your directory active configuration and correct them.

I will try to share with you some ideas about best practices for Securing Active Directory.

You can start by reading this link : Best Practices for Securing Active Directory

I recommend you to start by protect your accounts with privilege by implementing a tiers model in order to avoid privilege escalation in case on credential compromise.

You can also implement a bastion forest to enforce the security of privileged accounts.

I invite you to read the following links:

Planning a bastion environment

Tier model for partitioning administrative privileges

You should also check if:

• Password of domain account (Admin and standard user) use a complex password through a password policy
• Disable vulnerable protocols like ntlmv1, smbv1 , RC4 ...ect
• Privileged accounts with SPN (service principal name) configuration can be vulnerable to offline brute-forcing and dictionary attacks

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