Active Directory (AD) remains the backbone of identity, authentication, and authorization in most enterprise environments. Despite years of awareness around AD attacks—Kerberoasting, Pass-the-Hash, ACL abuse, delegation misconfigurations—many organizations still operate with legacy misconfigurations and excessive privileges that quietly expand their attack surface.
This is where Purple Knight, a free Active Directory security assessment tool by Semperis, plays a unique role. Rather than acting as an exploitation framework or red-team tool, Purple Knight positions itself as a security posture assessment and exposure discovery platform for Active Directory and Azure AD hybrid environments. This blog takes a practical VAPT-centric view of Purple Knight—what it does well, where it falls short, and how security teams can effectively use it during internal assessments.
It performs over 100 security checks across:
- On-prem Active Directory
- Azure Active Directory (Entra ID)
- Hybrid identity configurations
The tool produces a risk-scored report highlighting exploitable conditions, misconfigurations, and insecure legacy settings that attackers commonly abuse. Purple Knight does not exploit vulnerabilities, it identifies conditions that enable exploitation.
Primary Use Cases:
1. Internal VAPT & Assumed Breach Assessments:
Purple Knight proves especially valuable during internal VAPT engagements, assumed breach assessments, and purple team exercises, where the focus is on identifying what an attacker could realistically exploit after gaining an initial foothold. Instead of generic vulnerability listing, it quickly highlights high-risk Active Directory misconfigurations and identity weaknesses that would likely be abused first, helping security teams understand potential lateral movement paths and prioritize remediation based on real-world attack scenarios rather than theoretical exposure.
2. Active Directory Security Baseline Review:
Purple Knight is also highly effective for Active Directory security baseline reviews, particularly in environments that have evolved over many years without consistent hardening. It enables security teams to assess Active Directory configurations against modern security best practices, uncover the presence of legacy and weak protocols that remain enabled, and expose insecure delegation settings or excessive permissions that increase the risk of privilege escalation and domain compromise.
3. Pre- and Post-Hardening Validation:
Purple Knight is well suited for pre- and post-hardening validation, allowing organizations to establish a clear security baseline before remediation activities begin and then re-run assessments afterward to verify that identified risks have been effectively reduced. This repeatable approach supports continuous improvement programs by providing measurable visibility into how Active Directory security posture evolves over time and ensuring that hardening efforts deliver tangible security gains rather than cosmetic changes.
What Purple Knight Checks?
Purple Knight covers a broad spectrum of Active Directory attack surfaces, including:
i. Authentication & Protocol Risks:
- NTLM usage
- Weak Kerberos configurations
- Legacy authentication protocols
- SMB signing status
ii. Privileged Access & Delegation:
- Excessive Domain Admin privileges
- Insecure delegation configurations
- Over-permissioned service accounts
- Privileged users without MFA (hybrid environments)
iii. Active Directory Objects & ACLs:
- Dangerous Access Control Entries (ACEs)
- Writable or poorly secured Group Policy Objects (GPOs)
- Unprotected high-value objects
- Orphaned or stale privileged accounts
iv. Hybrid Identity Risks:
- Azure AD synchronization misconfigurations
- Weak password protection policies
- Hybrid trust weaknesses
- Cloud-to-on-premises attack paths
v. Attack Path Indicators
- Conditions enabling privilege escalation
- Indicators of credential theft opportunities
- Lateral movement enablers
- Persistence mechanisms
Key Benefits of Purple Knight:
i. Safe for Production Environment: Purple Knight is safe for use in production environments as it relies entirely on read-only checks, performs no exploitation, and does not disrupt services, making it suitable even for highly regulated or heavily hardened infrastructures.
ii. Quick Time to Value: Purple Knight delivers quick time to value with minimal setup and rapid assessments, providing immediate visibility into Active Directory security posture, which makes it especially effective when assessment timelines are tight.
iii. Excellent for Non-Red-Team Stakeholders: Purple Knight is particularly well suited for non–red team stakeholders such as security teams, blue teams, IT administrators, and auditors, as its reports present Active Directory risks in a clear and accessible manner without requiring deep offensive security expertise to interpret the findings.
iv. Free and Accessible: Purple Knight is free and easily accessible, making it an attractive option for small organizations, security assessments with limited budgets, and learning or lab environments where cost-effective yet meaningful Active Directory security visibility is required.
Limitations & Drawbacks:
i. No Exploitation or Proof-of-Concept: Purple Knight does not perform exploitation or provide proof-of-concept validation, meaning it does not actively abuse misconfigurations, confirm attack feasibility, or demonstrate real-world impact. As a result, penetration testers must still validate and contextualize findings using tools such as BloodHound, PowerView, or manual attack techniques to confirm actual exploitability.
ii. Limited Attack Path Visualization: Purple Knight has limited attack path visualization compared to tools like BloodHound, as it does not provide graphical attack graphs or multi-hop privilege escalation chains, focusing instead on identifying misconfigurations rather than showing how an attacker would chain them together in practice.
iii. Not a Replacement for Red Teaming: Purple Knight should not be positioned as a penetration testing tool, an exploitation framework, or a replacement for red team operations. Instead, it serves as a complementary capability that enhances offensive testing by identifying high-risk identity and Active Directory weaknesses, while leaving exploitation and attack validation to dedicated red team tools and methodologies.
iv. Requires Contextual Interpretation: Purple Knight findings require contextual interpretation, as some identified issues may be acceptable by design, driven by business or operational constraints, or dependent on architectural decisions. Blindly remediating every finding without understanding its context can introduce instability or disrupt critical business processes.
Purple Knight fills an important gap in the security ecosystem. It gives organizations a clear, low-risk view of their Active Directory security posture, especially in hybrid environments where identity risks often go unnoticed. Used correctly, Purple Knight can significantly reduce blind spots in Active Directory security—but its findings gain real value only when combined with deeper technical validation and attack-path analysis.
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