> ## Documentation Index
> Fetch the complete documentation index at: https://rootea.es/llms.txt
> Use this file to discover all available pages before exploring further.

# Feline

> Verified writeups for the Feline machine of Hack The Box

# Feline

<p className="machine-summary"><span className="prompt"><code>\$ tldr</code></span> Tomcat ysoserial deser → SaltStack CVE-2020-1651 → docker.sock</p>

<div className="cve-row"><span className="cve-row-label">CVE / Bulletins:</span> <a className="cve-chip" href="https://nvd.nist.gov/vuln/detail/CVE-2020-9484" target="_blank" rel="noopener">CVE-2020-9484 ↗</a> <a className="cve-chip" href="https://nvd.nist.gov/vuln/detail/CVE-2020-1651" target="_blank" rel="noopener">CVE-2020-1651 ↗</a></div>

<div className="machine-meta">
  | ·                | ·                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
  | ---------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
  | Operating system | Linux                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
  | Difficulty       | Hard                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
  | Vector           | <span className="vbadge vbadge-web">Web</span>                                                                                                                                                                                                                                                                                                                                                                                                                          |
  | IP               | `10.10.10.205`                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
  | Retirement date  | 2021-02-20                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
  | Skills           | Information leakage in error message RCE by deserialization in Apache Tomcat with PersistentManager - CVE-2020-9484 \[RCE] Playing with Ysoserial - CommonsCollections2 Manipulating our session cookie (JSESSIONID) + Directory Path Traversal Playing with chisel \[Socks Proxy + Proxychains (socks5)] SaltStack Exploitation - CVE-2020-1651 Gaining root access to a container Playing with docker.sock file + Abusing Docker API \[Privilege Escalation] PIVOTING |
</div>

## Writeups

| Language | Author                   | Format | Link                                                      |
| -------- | ------------------------ | ------ | --------------------------------------------------------- |
| 🇪🇸 ES  | **S4vitar**              | Vídeo  | [Open](https://www.youtube.com/watch?v=0e91a_Pns2Q)       |
| 🇪🇸 ES  | **El Pingüino de Mario** | Vídeo  | [Open](https://www.youtube.com/watch?v=DMjiQ2V9Nvs)       |
| 🇬🇧 EN  | **0xdf**                 | Texto  | [Open](https://0xdf.gitlab.io/2021/02/20/htb-feline.html) |
| 🇬🇧 EN  | **IppSec**               | Vídeo  | [Open](https://www.youtube.com/watch?v=2QdK7tQUFac)       |

## Skill resources

Curated documentation for each technique listed in the *Skills* column above. Sources: HackTricks, GTFOBins, PortSwigger, etc.

| Skill                       | Source      | Link                                                                                       |
| --------------------------- | ----------- | ------------------------------------------------------------------------------------------ |
| Information Leakage         | HackTricks  | [Open](https://book.hacktricks.wiki/en/pentesting-web/information-leak.html)               |
| Insecure Deserialization    | PortSwigger | [Open](https://portswigger.net/web-security/deserialization)                               |
| Directory / Path Traversal  | PortSwigger | [Open](https://portswigger.net/web-security/file-path-traversal)                           |
| Port Forwarding / Pivoting  | HackTricks  | [Open](https://book.hacktricks.wiki/en/generic-hacking/tunneling-and-port-forwarding.html) |
| Remote Code Execution (RCE) | HackTricks  | [Open](https://book.hacktricks.wiki/en/pentesting-web/command-injection.html)              |

## Related skills worth mastering

Local File Inclusion (LFI) · Remote File Inclusion (RFI) · Shellshock (CVE-2014-6271)

## If you liked this machine, try

* [Talkative](/en/htb/machines/linux/dificil/talkative) — Linux, Hard
* [Jewel](/en/htb/machines/linux/medio/jewel) — Linux, Medium
* [Laboratory](/en/htb/machines/linux/facil/laboratory) — Linux, Easy
* [Monitors](/en/htb/machines/linux/dificil/monitors) — Linux, Hard
* [Oouch](/en/htb/machines/linux/dificil/oouch) — Linux, Hard

***

## Comments & tips

Did the official writeup not work? Found a smarter trick? Share it here — comments live in [GitHub Discussions](https://github.com/FFuson/HTB_Writeups/discussions).

<div className="rootea-giscus-wrap" data-giscus-term="machine:feline" data-giscus-lang="en" />

*Last updated: 2026-06-07*

<script type="application/ld+json">
  {`{"@context":"https://schema.org","@type":"TechArticle","headline":"Feline — HTB Writeup Index","name":"Feline","url":"https://rootea.es/en/htb/machines/linux/dificil/feline","inLanguage":"en","datePublished":"2021-02-20","dateModified":"2026-06-07","about":{"@type":"Thing","name":"Hack The Box (HTB)"},"keywords":"Information Leakage, Insecure Deserialization, Directory / Path Traversal, Port Forwarding / Pivoting, Remote Code Execution (RCE)","isPartOf":{"@type":"WebSite","name":"rootea.es","url":"https://rootea.es"},"author":{"@type":"Organization","name":"rootea.es"},"proficiencyLevel":"Difícil"}`}
</script>

<script type="application/ld+json">
  {`{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://rootea.es/en"},{"@type":"ListItem","position":2,"name":"Linux","item":"https://rootea.es/en/htb/machines/linux/dificil/index"},{"@type":"ListItem","position":3,"name":"Hard","item":"https://rootea.es/en/htb/machines/linux/dificil/index"},{"@type":"ListItem","position":4,"name":"Feline","item":"https://rootea.es/en/htb/machines/linux/dificil/feline"}]}`}
</script>