{"id":201,"date":"2025-01-17T00:00:00","date_gmt":"2025-01-16T23:00:00","guid":{"rendered":"https:\/\/kosokoking.com\/?p=201"},"modified":"2025-01-15T16:27:22","modified_gmt":"2025-01-15T15:27:22","slug":"mastering-acl-escalation-in-ad-best-practices","status":"publish","type":"post","link":"https:\/\/kosokoking.com\/index.php\/multifarious\/mastering-acl-escalation-in-ad-best-practices\/","title":{"rendered":"Mastering ACL Escalation in AD: Best Practices!"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Introduction<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This guide outlines a practical playbook for identifying and exploiting weak Access Control Lists (ACLs) in Active Directory environments, along with steps to remediate any configuration issues and maintain security posture.&nbsp;The purpose of this guide is to provide both offensive and defensive teams with an understanding of ACL abuse and its mitigation.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Prerequisites<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>User Credentials<\/strong>: Valid credentials with sufficient privileges to change passwords and add members to AD groups.<\/li>\n\n\n\n<li><strong>PowerView, Rubeus, or Similar Tools<\/strong>: For executing actions such as changing passwords, enumerating groups, Kerberoasting, and performing ACL analysis.<\/li>\n\n\n\n<li><strong>Secure Environment<\/strong>: A lab or approved testing environment for any planned exploit attempts.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Attack Chain Overview<\/h2>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Acquire Target Credentials<\/strong>\n<ul class=\"wp-block-list\">\n<li>Obtain the hash of an account with the necessary privileges (for example, using Responder or cracking NTLMv2 hashes offline).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Password Changes \/ Group Membership<\/strong>\n<ul class=\"wp-block-list\">\n<li>Abuse ACL rights (GenericWrite, GenericAll) to change a target user\u2019s password or add a compromised account to a high-value group.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Nested Group Escalation<\/strong>\n<ul class=\"wp-block-list\">\n<li>Take advantage of nested group memberships to elevate privileges further, potentially leading to Domain Admin access.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Kerberoasting<\/strong>\n<ul class=\"wp-block-list\">\n<li>Set a fake Service Principal Name (SPN) on an admin or service account, request the service ticket, and crack the resulting hash offline if feasible.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Detailed Steps<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Step 1: Change Target User\u2019s Password<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Create PSCredential objects for the compromised user.<\/li>\n\n\n\n<li>Use tools like PowerView\u2019s Set-DomainUserPassword to force a password reset on a chosen account.<\/li>\n\n\n\n<li>Confirm the password change was successful by authenticating as the target user.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Step 2: Modify Group Membership<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Create another PSCredential object using the newly accessed target user\u2019s credentials.<\/li>\n\n\n\n<li>Add the user to a group that grants membership inheritance or direct privilege escalation (e.g., Help Desk Level 1 or Information Technology) via Add-DomainGroupMember.<\/li>\n\n\n\n<li>Verify that the user was successfully added to the group.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Step 3: Abuse Nested Group Rights<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Inherit elevated permissions from nested group membership.<\/li>\n\n\n\n<li>Leverage GenericAll or GenericWrite to escalate to high-privileged accounts (e.g., by resetting passwords or setting SPNs on admin users).<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Step 4: Kerberoasting (Optional Escalation)<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>Assign a fake SPN to an account with high privileges using Set-DomainObject.<\/li>\n\n\n\n<li>Request a Kerberos ticket with Rubeus or similar.<\/li>\n\n\n\n<li>Save the ticket hash and attempt to crack offline.<\/li>\n\n\n\n<li>Use any recovered credentials to perform advanced attacks like a DC synchronization (DCSync).<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Cleanup<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Remove Fake SPNs<\/strong>: Clear the servicePrincipalName attribute from the compromised account.<\/li>\n\n\n\n<li><strong>Restore Group Membership<\/strong>: Remove the compromised user from any privileged groups added during testing.<\/li>\n\n\n\n<li><strong>Revert Password Changes<\/strong>: Restore original passwords or let the legitimate user update them.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Detection<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Audit and Remove Risky ACLs<\/strong>: Regularly check permissions in Active Directory, focusing on critical paths.<\/li>\n\n\n\n<li><strong>Monitor Group Membership<\/strong>: Track memberships for groups with high privileges, alerting the security team to unusual additions.<\/li>\n\n\n\n<li><strong>Advanced Security Audit Policy<\/strong>: Enable relevant event IDs (e.g., 5136) to detect modifications to objects in real time.<\/li>\n\n\n\n<li><strong>Use Tools for Monitoring<\/strong>: Employ solutions like BloodHound to visualise and detect dangerous ACL paths.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Remediation Strategies<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When ACL abuse is detected or suspected:<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Immediate Actions<\/strong>\n<ul class=\"wp-block-list\">\n<li>Isolate affected systems.<\/li>\n\n\n\n<li>Revoke compromised credentials.<\/li>\n\n\n\n<li>Remove unauthorised group memberships.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>ACL Clean-up<\/strong>\n<ul class=\"wp-block-list\">\n<li>Review and remove dangerous ACLs.<\/li>\n\n\n\n<li>Implement least-privilege access model.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Password Resets<\/strong>\n<ul class=\"wp-block-list\">\n<li>Force password changes for affected accounts.<\/li>\n\n\n\n<li>Consider implementing multi-factor authentication.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>System Hardening<\/strong>\n<ul class=\"wp-block-list\">\n<li>Patch vulnerabilities<\/li>\n\n\n\n<li>Strengthen password policies.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Best Practices<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Proactively protect against ACL abuse with these best practices:<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Regular AD Audits<\/strong>\n<ul class=\"wp-block-list\">\n<li>Conduct periodic reviews of ACLs and group memberships.<\/li>\n\n\n\n<li>Use tools like BloodHound to identify potential attack paths.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Principle of Least Privilege<\/strong>\n<ul class=\"wp-block-list\">\n<li>Grant minimal necessary permissions to users and groups<\/li>\n\n\n\n<li>Regularly review and revoke unnecessary access.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Separation of Duties<\/strong>\n<ul class=\"wp-block-list\">\n<li>Implement role-based access control.<\/li>\n\n\n\n<li>Avoid concentration of privileges in single accounts<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Employee Training<\/strong>\n<ul class=\"wp-block-list\">\n<li>Educate IT staff on ACL management and security implications.<\/li>\n\n\n\n<li>Train users on security awareness and password hygiene<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Continuous Monitoring<\/strong>\n<ul class=\"wp-block-list\">\n<li>Implement real-time alerting for critical AD changes.<\/li>\n\n\n\n<li>Regularly review and analyse AD logs.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Additional Resources<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/docs.microsoft.com\/en-us\/windows-server\/identity\/ad-ds\/plan\/security-best-practices\/best-practices-for-securing-active-directory\" target=\"_blank\" rel=\"noreferrer noopener\">Microsoft Documentation: Active Directory Security Best Practices<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/attack.mitre.org\/tactics\/TA0006\/\" target=\"_blank\" rel=\"noreferrer noopener\">MITRE ATT&amp;CK: Active Directory<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.sans.org\/blog\/active-directory-security\/\" target=\"_blank\" rel=\"noreferrer noopener\">SANS Institute: Active Directory Security<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/github.com\/BloodHoundAD\/BloodHound\" target=\"_blank\" rel=\"noreferrer noopener\">BloodHound: Active Directory Security Tool<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/github.com\/PowerShellMafia\/PowerSploit\/tree\/master\/Recon\" target=\"_blank\" rel=\"noreferrer noopener\">PowerView: AD Enumeration and Exploitation Tool<\/a><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">By following this playbook, organisations can significantly improve their ability to prevent, detect, and respond to ACL abuse tactics in their Active Directory environments.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Boost domain security with proven tips on identifying, exploiting, and mitigating ACL weaknesses in Active Directory. Secure access, protect every account.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[87,113,51,18,21,14],"class_list":["post-201","post","type-post","status-publish","format-standard","hentry","category-multifarious","tag-acl","tag-acls","tag-cybersecurity","tag-explainer","tag-functionality","tag-security"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/posts\/201","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/comments?post=201"}],"version-history":[{"count":1,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/posts\/201\/revisions"}],"predecessor-version":[{"id":202,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/posts\/201\/revisions\/202"}],"wp:attachment":[{"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/media?parent=201"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/categories?post=201"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kosokoking.com\/index.php\/wp-json\/wp\/v2\/tags?post=201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}