Active Directory (Part 12.2)

By Ashwin Venugopal -

 






Exploitation

Several methods can be used to exploit misconfiguration in an Active Directory environment. Such methods includes AD delegation, forcing authentication relays, targeting AD users, domain trusts, and using Group Policy Objects or Silver and Golden Tickets. Other methods can also be used according to the AD environment.

Automated Relays- They allow authentication credentials to be forwarded or "relayed" from one system to another. These relays can be established via various protocols and techniques like SMB, NTLM, Kerberos, and others. A penetration tester can use automated relays to capture and use credentials to gain unauthorized access to sensitive information or resources within the AD environment. 

Printer bug is a vulnerability that affects certain versions of the Microsoft Windows operating systems. It allows an attacker to remotely execute arbitrary code on a system by sending a specially crafted print job to a printer that is shared on the network. So, in an AD environment, this bug can be potentially used to gain unauthorized access to sensitive information or resources. However, to exploit this, apart from machine account administrative privileges, there are also another four conditions that should be met:

  1. A valid set of AD account credentials.
  2. Network connectivity to the target's SMB service.
  3. The target host must be running the Print Spooler service.
  4. The hosts must not have SMB signing enforced.

Also, to relay the forced authentication attempt through SMB, it is necessary to disable the enforcement of SMB signing. By default, the SMB signing is allowed but not enforced, i.e., it will only be used if supported. However, if a malicious SMB server is set up, it is possible to disable support for SMB signing, forcing the target system not to sign the SMB authentication attempt during the relay process. 

AD Users- Habits and practices of users (like having weak passwords or offering excessive permissions), sometimes make them the weakest link in an organization's security chain.  Hence, this aspect is also important to consider while attacking an AD environment. Credential management is beneficial because users may have multiple sets of credentials and may struggle to remember all of them. Keylogging can be a useful tool for attackers to understand how normal users interact with a system, along with screen captures. 

GPOs- A GPO is a virtual collection of policy settings. Each GPO has a unique name, called GUID. each Windows computer has a Local Policy Configuration containing several notable configurations like: 
  1. Application configuration for services like the Firewall, Anti-Virus, and Applocker. 
  2. Local Group membership such as the Administrator or Remote Desktop Users groups.
  3. Startup configuration like scripts should be executed.
  4. Security and protocol settings such as SMBv1 support. 
Although there are several ways in which GPOs can be exploited, but if the penetration tester has an AD account he controls that is both local Administrator and local Remote Desktop User, then, it will allow him administrative privileges on a machine and the ability to RDP in. To modify the GPO, the tester will have to access Group Policy Management as the AD user having relevant permissions. 

Conclusion

This part discovers more exploitation methods in an AD environment. 












































Comments

Post a Comment

Popular posts from this blog

Deployment (Part 3)

By Ashwin Venugopal -
Image
  To read part 1, please click  here To read part 2, please click  here Microsoft Monitoring Agent (MMA) MMA is used across multiple Microsoft solutions and has undergone a few name changes as its features and functionality have evolved. If it is being considered to be used, then following areas should be covered during a Microsoft Sentinel deployment project: Consider the timelines and the strategy for a migration to AMA (Azure Monitor Agent) before the MMA end-of-life.  Consider the central deployment and management methodology for MMA. Determine which endpoints are in scope for deployment as these affect the log ingestion volume significantly.  Azure Monitor Agent (AMA) Organizations with MMA as the main Microsoft Sentinel agent should start planning the migration to AMA as soon as possible to avoid a rushed migration. One of the main advantages of AMA is the ability to control the log collection policy centrally and apply different policies against different groups of computers, re
Read more

Project Resourcing (Part 2)

By Ashwin Venugopal -
Image
  To read part 1, please click  here Engineering - SIEM The SIEM engineers configures Microsoft Sentinel, including Log Analytics, Logic Apps, workbooks, and playbooks. They are also responsible for the following high-level tasks: Initial configuration of Azure tenant, including provisioning required resources, assigning access roles, and configuring workspace parameters like log retention, resource tagging, and blueprints.  Deployment and configuration of syslog/CEF log collection agents in appropriate locations to collect logs from on-premises devices. Generally, it will be joint effort of both system engineer and SIEM engineer, involving configuration and potential troubleshooting.  Working with system owners to enable log forwarding and configuring any required parsing of log data in Log Analytics.  Working with security operations to create and deploy KQL analytic rules to offer detections for SOC/Computer Security Incident Response Team (CSRIT) use. Tuning of alert rule parameter
Read more

Design Planning (Part 3)

By Ashwin Venugopal -
Image
  To read part 1, please click  here To read part 2, please click  here Complex Organizational Structures SIEM can be an expensive security control, hence, it is common multiple businesses to contribute to the overall expense. Various organizational units may require a level of access to specific dashboards or sets of data. Microsoft Sentinel offers the ability to assign table-level permissions and limit the level of access to the minimum required to perform requisite job functions.  Role-based Access Control (RBAC) Requirements Microsoft Sentinel offers an extensive list of Azure built-in roles that can be used to provide granular access according to the job requirements and permitted level of access. Some of them are various Microsoft Sentinel dedicated roles: Microsoft Sentinel Contributor- Can perform all engineering-related configuration, such as creating alert rules, configuring data connectors, and additional similar tasks.  Microsoft Sentinel Reader- Can query the log data stor
Read more