Cewl

cewl Agent Skill

When to Use This Skill

Use this skill when:

• The user needs target-specific wordlists built from a company's website
• Performing password spraying against Active Directory or web apps where employees write content
• Extracting email addresses from a web target for phishing or username enumeration
• Harvesting metadata (author names, software) from documents linked on a site
• Building a wordlist → rules → cracker pipeline for a password audit

What CeWL Does

CeWL (Custom Word List generator) is a Ruby application that spiders a given URL to a specified depth and returns a list of words found on the site. These words are useful as password candidates because real employees write company-specific jargon, product names, and internal terms that generic wordlists miss. CeWL is maintained by Robin Wood (digininja) and has ~2.7k GitHub stars.

Installation

Kali Linux / Debian (apt — recommended)

sudo apt update && sudo apt install -y cewl
cewl --version

Ruby Gem (latest version)

# Requires Ruby >= 2.5
gem install cewl
# Or install from source
git clone https://github.com/digininja/CeWL.git /opt/cewl
cd /opt/cewl
bundle install
ruby cewl.rb --help

Dependency Check

gem list | grep -E "nokogiri|spider|mime|mini_exiftool"
# If missing: bundle install inside /opt/cewl

Core Concepts

Spidering

CeWL fetches the target URL and follows links up to the specified depth (-d). It stays within the same domain by default, preventing drift to external sites. Every word on visited pages is extracted, deduplicated, and optionally filtered by minimum length.

Word Extraction Rules

• HTML tags, attributes, and JavaScript are stripped; only visible text content is kept
• Numbers-only strings are excluded by default
• Words are case-sensitive unless --lowercase is used
• Duplicate words are removed (each word appears once)

Email and Metadata Extraction

• --email extracts mailto: addresses and @-format strings found in text
• --meta reads metadata from linked documents (PDF, DOCX, XLSX, PPTX) using ExifTool

CLI Reference

Basic Usage

# Simple wordlist from a URL, output to stdout
cewl https://www.target.com

# Save to file
cewl https://www.target.com -w /tmp/target_words.txt

# Specify depth (default: 2; 0 = current page only)
cewl https://www.target.com -d 3 -w /tmp/words_deep.txt

# Minimum word length (default: 3)
cewl https://www.target.com -m 6 -w /tmp/words_6plus.txt

# Count word occurrences (outputs "word, count" format)
cewl https://www.target.com -c -w /tmp/words_counted.txt

Depth and Scope

# Depth 0: only the single page given
cewl https://www.target.com/about -d 0 -w /tmp/about_only.txt

# Depth 1: target page + all directly linked pages
cewl https://www.target.com -d 1 -m 5 -w /tmp/d1.txt

# Depth 4: aggressive spidering (slower, more coverage)
cewl https://www.target.com -d 4 -m 4 -w /tmp/d4_words.txt

# Offsite links: follow links to external domains
cewl https://www.target.com --offsite -d 2 -w /tmp/offsite.txt

Email Extraction

# Extract emails to stdout (alongside wordlist)
cewl https://www.target.com -e

# Save emails to a separate file
cewl https://www.target.com -e --email_file /tmp/emails.txt -w /tmp/words.txt

# Emails + wordlist in one run
cewl https://www.target.com -d 3 -m 5 \
  -e --email_file /tmp/emails.txt \
  -w /tmp/words.txt

Metadata Extraction

# Extract metadata from linked documents (PDF, DOCX, etc.)
# Requires: exiftool (sudo apt install libimage-exiftool-perl)
cewl https://www.target.com --meta -w /tmp/words.txt

# Save metadata to separate file
cewl https://www.target.com --meta --meta_file /tmp/meta.txt -w /tmp/words.txt

# Full run: words + emails + metadata
cewl https://www.target.com -d 3 -m 4 \
  -e --email_file /tmp/emails.txt \
  --meta --meta_file /tmp/meta.txt \
  -w /tmp/full_wordlist.txt

Case and Formatting

# Lowercase all words (deduplicated after lowercasing)
cewl https://www.target.com --lowercase -w /tmp/lower.txt

# Convert to uppercase post-processing
cewl https://www.target.com -w - | tr '[:lower:]' '[:upper:]' > /tmp/upper.txt

# Remove words shorter than N after CeWL (additional filter)
cewl https://www.target.com -m 3 -w - | awk 'length >= 8' > /tmp/min8.txt

Authentication

# HTTP Basic authentication
cewl https://intranet.target.com \
  --auth_type basic \
  --auth_user admin \
  --auth_pass password123 \
  -w /tmp/intranet_words.txt

# HTTP Digest authentication
cewl https://intranet.target.com \
  --auth_type digest \
  --auth_user jsmith \
  --auth_pass Summer2024! \
  -d 2 -m 5 -w /tmp/digest_words.txt

# Cookie-based authentication (supply session cookie)
cewl https://app.target.com/dashboard \
  --header "Cookie: session=abc123; PHPSESSID=xyz" \
  -w /tmp/auth_words.txt

Proxy Support

# HTTP proxy (Burp Suite for inspection)
cewl https://www.target.com \
  --proxy_host 127.0.0.1 \
  --proxy_port 8080 \
  -w /tmp/words.txt

# Proxy with credentials
cewl https://www.target.com \
  --proxy_host proxy.corp.com \
  --proxy_port 3128 \
  --proxy_username user \
  --proxy_password pass \
  -w /tmp/words.txt

User-Agent Customization

# Custom user-agent string (bypass WAF or appear as Googlebot)
cewl https://www.target.com \
  --user-agent "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
  -w /tmp/words.txt

cewl https://www.target.com \
  --user-agent "Googlebot/2.1 (+http://www.google.com/bot.html)" \
  -w /tmp/words.txt

Additional Options

# Follow redirects (default: yes)
cewl https://www.target.com --no_follow_redirect -w /tmp/words.txt

# Verbose output (shows pages visited)
cewl https://www.target.com -v -w /tmp/words.txt

# Debug output
cewl https://www.target.com --debug -w /tmp/words.txt

# Rate limiting (add delay between requests, in seconds)
cewl https://www.target.com --rate-limit 1 -w /tmp/words.txt

# Include numbers in wordlist
cewl https://www.target.com --with-numbers -w /tmp/words_nums.txt

Common Workflows

Standard Password List Build

# 1. Spider target with good coverage
cewl https://www.target.com -d 3 -m 5 --lowercase \
  -e --email_file /tmp/target_emails.txt \
  -w /tmp/cewl_raw.txt

# 2. Check word count
wc -l /tmp/cewl_raw.txt

# 3. Sort and deduplicate
sort -u /tmp/cewl_raw.txt -o /tmp/cewl_sorted.txt

CeWL → Rules → Hashcat Pipeline

# 1. Generate wordlist
cewl https://www.target.com -d 3 -m 5 -w /tmp/cewl.txt

# 2. Apply hashcat rules to expand (capitalize, add numbers, symbols)
hashcat -a 0 -m 1000 /tmp/ntlm_hashes.txt /tmp/cewl.txt \
  -r /usr/share/hashcat/rules/best64.rule \
  -r /usr/share/hashcat/rules/toggles1.rule \
  --status --status-timer=30

# 3. Additional rules: append years and common suffixes
hashcat -a 0 -m 1000 /tmp/ntlm_hashes.txt /tmp/cewl.txt \
  -r /usr/share/hashcat/rules/d3ad0ne.rule \
  -o /tmp/cracked.txt

CeWL → John the Ripper

# Generate wordlist
cewl https://www.target.com -d 2 -m 6 -w /tmp/cewl.txt

# Run john with rules
john --wordlist=/tmp/cewl.txt \
  --rules=best64 \
  --format=NT \
  /tmp/hashes.txt

# Show cracked passwords
john --show /tmp/hashes.txt

CeWL → Hydra (Online Attack)

# 1. Build wordlist
cewl https://www.target.com -d 3 -m 6 --lowercase -w /tmp/cewl.txt

# 2. Use emails as usernames, CeWL words as passwords
# Extract just usernames from emails
cut -d@ -f1 /tmp/emails.txt > /tmp/usernames.txt

# 3. Spray against OWA/Office 365
hydra -L /tmp/usernames.txt -P /tmp/cewl.txt \
  https-post-form \
  "https://mail.target.com/owa/auth.owa:username=^USER^&password=^PASS^:failed" \
  -t 1 -w 3 -V

# 4. Spray against SMB
hydra -L /tmp/usernames.txt -P /tmp/cewl.txt \
  smb://10.10.10.5 -t 1 -W 5

Intranet Portal Wordlist

# Spider internal wiki/portal with credentials
cewl https://wiki.internal.corp \
  --auth_type basic \
  --auth_user pentest \
  --auth_pass Temp1234! \
  -d 4 -m 4 \
  --meta --meta_file /tmp/meta_authors.txt \
  -e --email_file /tmp/internal_emails.txt \
  -w /tmp/internal_words.txt

# Authors from metadata = likely usernames
cat /tmp/meta_authors.txt

Advanced Techniques

Merging Multiple CeWL Runs

# Spider multiple targets (blog, main site, careers page)
for url in \
  "https://www.target.com" \
  "https://blog.target.com" \
  "https://careers.target.com"; do
    cewl "$url" -d 2 -m 5 --lowercase -w /tmp/cewl_$(date +%s).txt
done

# Merge and deduplicate
cat /tmp/cewl_*.txt | sort -u > /tmp/master_wordlist.txt
wc -l /tmp/master_wordlist.txt

Post-Processing with Python

#!/usr/bin/env python3
# Expand CeWL wordlist with common password patterns
words = open('/tmp/cewl.txt').read().splitlines()
output = []
for w in words:
    output.append(w)
    output.append(w.capitalize())
    output.append(w + '1')
    output.append(w + '123')
    output.append(w + '2024')
    output.append(w + '!')
    output.append(w[0].upper() + w[1:] + '!')
with open('/tmp/cewl_expanded.txt', 'w') as f:
    f.write('\n'.join(set(output)))
print(f"Generated {len(set(output))} candidates")

Combining with Crunch for Hybrid Lists

# CeWL base words + Crunch numeric suffixes
cewl https://www.target.com -d 2 -m 6 -w /tmp/base.txt
# Append 4-digit year to each word
while read word; do
  crunch 4 4 1234567890 | while read num; do echo "${word}${num}"; done
done < /tmp/base.txt > /tmp/hybrid.txt

Integration with Other Tools

Tool	Integration
Hashcat	Primary cracker; use CeWL words with -a 0 + rules
John the Ripper	--wordlist=cewl.txt --rules=best64
Hydra	-P cewl.txt for online password spraying
Medusa	-P cewl.txt for multi-protocol online attacks
Burp Suite	Proxy CeWL through Burp to inspect/modify requests
SpiderFoot	OSINT to find additional subdomains; CeWL each subdomain
Crunch	Generate numeric/symbol suffixes to append to CeWL words
Metasploit	auxiliary/scanner/smb/smb_login with CeWL wordlist

Troubleshooting

SSL certificate errors

# Ignore SSL verification
cewl https://self-signed.target.com --no-verify-ssl -w /tmp/words.txt

Too few words generated

• Lower -m to 3 or 4
• Increase -d depth
• Add --offsite if relevant content is on subdomains
• Try specific content pages: /blog, /news, /about
• The site may be JavaScript-heavy (CeWL cannot render JS) — use wget --mirror first and run CeWL on local files

JavaScript-rendered sites

# Download rendered HTML with a headless browser first
chromium --headless --dump-dom https://www.target.com > /tmp/rendered.html
# Serve locally and point CeWL at it
python3 -m http.server 8888 --directory /tmp &
cewl http://127.0.0.1:8888/rendered.html -d 0 -w /tmp/words.txt

ExifTool missing for --meta

sudo apt install libimage-exiftool-perl -y
exiftool --version

Rate-limited by WAF

cewl https://www.target.com --rate-limit 2 \
  --user-agent "Mozilla/5.0 (compatible; Googlebot/2.1)" \
  -w /tmp/words.txt

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