Proving Grounds - DC-9 (Linux)
Proving Grounds DC-9 Linux walkthrough covering reconnaissance, initial access, and privilege escalation.
Overview
| Field | Value |
|---|---|
| OS | Linux |
| Difficulty | Not specified |
| Attack Surface | Web application and exposed network services |
| Primary Entry Vector | Web-based initial access |
| Privilege Escalation Path | Local enumeration -> misconfiguration abuse -> root |
Credentials
No credentials obtained.
Reconnaissance
At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
No additional logs saved.
💡 Why this works
This stage maps the reachable attack surface and identifies where exploitation is most likely to succeed. Accurate service and content discovery reduces blind testing and drives targeted follow-up actions.
Initial Foothold
Caption: Screenshot captured during this stage of the assessment.
http://192.168.205.209/search.php 
Caption: Screenshot captured during this stage of the assessment.
Caption: Screenshot captured during this stage of the assessment.
Caption: Screenshot captured during this stage of the assessment.
At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
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ID: 1<br/>Name: admin 856f5de590ef37314e7c3bdf6f8a66dc<br/>Position: 4<br />Phone No: 5<br />Email: 6<br/><br/>
<br /><br />
Caption: Screenshot captured during this stage of the assessment.
Caption: Screenshot captured during this stage of the assessment.
http://192.168.205.209/welcome.php?file=../../../../../../../../etc/passwd 
Caption: Screenshot captured during this stage of the assessment.
At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
No additional logs saved.
💡 Why this works
The initial access step chains discovered weaknesses into executable control over the target. Successful foothold techniques are validated by command execution or interactive shell callbacks.
Privilege Escalation
At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
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sudo権限あり
Matching Defaults entries for fredf on dc-9: env_reset, mail_badpass, secure_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin User fredf may run the following commands on dc-9: Sudoers entry: RunAsUsers: root Options: !authenticate Commands: /opt/devstuff/dist/test/test At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
No additional logs saved.
💡 Why this works
Privilege escalation relies on local misconfigurations, unsafe permissions, and trusted execution paths. Enumerating and abusing these trust boundaries is the fastest route to root-level access.
Lessons Learned / Key Takeaways
- Validate framework debug mode and error exposure in production-like environments.
- Restrict file permissions on scripts and binaries executed by privileged users or schedulers.
- Harden sudo policies to avoid wildcard command expansion and scriptable privileged tools.
- Treat exposed credentials and environment files as critical secrets.
Attack Flow
At this stage, the following command(s) are executed to progress the attack chain and validate the next hypothesis. We are specifically looking for actionable indicators such as open services, exploitability, credential exposure, or privilege boundaries. Key flags and parameters are preserved to keep the workflow reproducible for follow-along testing.
No additional logs saved.
References
- RustScan: https://github.com/RustScan/RustScan
- Nmap: https://nmap.org/
- feroxbuster: https://github.com/epi052/feroxbuster
- Nuclei: https://github.com/projectdiscovery/nuclei
- GTFOBins: https://gtfobins.org/
- HackTricks Privilege Escalation: https://book.hacktricks.wiki/en/linux-hardening/privilege-escalation/index.html