What it does. Enumerate and audit Active Directory forest trust relationships using Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).

Install

• npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill performing-active-directory-forest-trust-attack, or copy the skill folder into ~/.claude/skills/performing-active-directory-forest-trust-attack/.
• Raw file: curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/performing-active-directory-forest-trust-attack/SKILL.md

SKILL.md (verbatim)

name: performing-active-directory-forest-trust-attack
description: Enumerate and audit Active Directory forest trust relationships using
  Impacket for SID filtering analysis, trust key extraction, cross-forest SID history
  abuse detection, and inter-realm Kerberos ticket assessment. Use when red-teaming
  multi-forest AD environments or auditing forest trusts for cross-forest privilege
  escalation and trust ticket forgery exposure.
domain: cybersecurity
subdomain: red-team
tags:
- active-directory
- forest-trust
- impacket
- SID-filtering
- kerberos
- red-team
- trust-enumeration
version: '1.0'
author: mahipal
license: Apache-2.0
nist_csf:
- ID.RA-01
- GV.OV-02
- DE.AE-07
mitre_attack:
- T1595
- T1190
- T1059
- T1078
- T1558.003

Performing Active Directory Forest Trust Attack

Overview

Active Directory forest trusts enable authentication across organizational boundaries but introduce attack surface if misconfigured. This skill uses impacket to enumerate trust relationships, analyze SID filtering configuration, detect SID history abuse vectors, perform cross-forest SID lookups via LSA/LSAT RPC calls, and assess inter-realm Kerberos ticket configurations for trust ticket forgery risks.

When to Use

• When conducting security assessments that involve performing active directory forest trust attack
• When following incident response procedures for related security events
• When performing scheduled security testing or auditing activities
• When validating security controls through hands-on testing

Prerequisites

• Python 3.9+ with impacket, ldap3
• Domain credentials with read access to AD trust objects
• Network access to Domain Controllers (ports 389, 445, 88)
• Authorized penetration testing engagement or lab environment

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Steps

1. Enumerate forest trust relationships via LDAP trusted domain objects
2. Query trust attributes and SID filtering status for each trust
3. Perform SID lookups across trust boundaries using LsarLookupNames3
4. Enumerate foreign security principals in trusted domains
5. Check for SID history on cross-forest accounts
6. Assess trust direction and transitivity for lateral movement paths
7. Generate trust security audit report with risk findings

Expected Output

• JSON report listing all trust relationships, SID filtering status, foreign principals, trust direction/transitivity, and risk assessment
• Cross-forest attack path analysis with remediation recommendations

Other files in this skill

• LICENSE
• references/api-reference.md
• scripts/agent.py

references/api-reference.md (verbatim)

API Reference — Performing Active Directory Forest Trust Attack

Libraries Used

• impacket: SMB/RPC transport for LSA SID lookups via lsat.hLsarLookupSids2()
• ldap3: LDAP queries against trustedDomain objects and foreignSecurityPrincipal containers
• json: JSON serialization for audit reports

CLI Interface

python agent.py --dc 10.0.0.1 --domain corp.local --username admin --password Pass123 trusts
python agent.py --dc 10.0.0.1 --domain corp.local --username admin --password Pass123 foreign
python agent.py --dc 10.0.0.1 --domain corp.local --username admin --password Pass123 lookup-sid --sid S-1-5-21-...
python agent.py --dc 10.0.0.1 --domain corp.local --username admin --password Pass123 full

Core Functions

enumerate_trusts_ldap(dc_host, domain, username, password) — Trust enumeration

LDAP search: (objectClass=trustedDomain) under CN=System,DC=.... Attributes: trustPartner, trustDirection, trustType, trustAttributes, flatName. Decodes trust attribute bitmask for SID filtering, forest transitivity, RC4 encryption.

enumerate_foreign_principals(dc_host, domain, username, password) — Cross-forest members

LDAP search: (objectClass=foreignSecurityPrincipal) under CN=ForeignSecurityPrincipals. Filters well-known SIDs (S-1-5-x with 3 dashes). Returns group memberships.

lookup_sid_cross_forest(dc_host, domain, username, password, target_sid) — LSA SID resolution

Opens SMB transport to \lsarpc, binds MSRPC_UUID_LSAT, calls hLsarLookupSids2(). Resolves SIDs across trust boundaries.

assess_trust_risk(trusts, foreign_principals) — Risk scoring

Scoring: +40 SID filtering disabled, +20 RC4 encryption, +15 bidirectional trust, +10 forest transitive.

full_audit(dc_host, domain, username, password) — Comprehensive audit

Trust Direction Values

Trust Attribute Flags

Impacket RPC Calls

Dependencies

• impacket >= 0.11.0
• ldap3 >= 2.9.0
• Network access to DC ports 389 (LDAP), 445 (SMB), 88 (Kerberos)

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