Capture the Flag! Command Injection by Docker Layers
Source: YouTube · John Hammond · published Dec 5, 2024 · 42:46
This video analyzes a CTF challenge involving container registry vulnerabilities where the real vulnerability was a tar command injection in the build.sh script 1:26-1:30, allowing attackers to execute arbitrary code.
Key Takeaways:
• The CTF challenge involved five services including a custom image builder service that processed Docker images 0:37-0:42
• The goal was to access a privileged "service user" account to find the flag in the Checker image 2:28-2:33
• The critical vulnerability was in the build.sh script where the layer variable wasn't properly quoted, creating a command injection point 10:46-10:52
• Attackers bypassed whitespace restrictions by using hex-encoded spaces (\x20) in the Docker image configuration 12:20-12:26
• The exploit involved crafting a malicious Docker image with modified config files to overwrite system files 21:34-21:36
This video demonstrates how seemingly minor code vulnerabilities in container processing pipelines can lead to complete system compromise.
Sources:
- 0:37-0:42 Overview of the five services in the CTF challenge
- 1:26-1:30 Description of the vulnerability in the build.sh script
- 2:28-2:33 Explanation of the service user account and challenge goal
- 10:46-10:52 Analysis of the command injection vulnerability
- 12:20-12:26 Hex-encoded space bypass technique
- 21:34-21:36 File over
Generate CPE Credits
Generate a professional CPE document from this video's transcript.
Estimated credit: 0.5 CPE hours
Estimate uses the video runtime (1 hour ≈ 1 CPE, rounded to the nearest 0.5, minimum 0.5, maximum 2.0). The final amount can be lower after review, never higher.
Topic: Cybersecurity. Commonly maps to: Security and Risk Management, Security Operations. Exact CISSP domains are assigned during generation.
Free account. One generation at a time, with a daily limit.
CPEBuddy is independent and not affiliated with or endorsed by ISC2, ISACA, or any certification body. Exports are formatted for common CPE submissions; acceptance is at your certification body's discretion.
Transcript Preview
First 800 characters of the transcript
this is a writeup that was recently posted on CTF time.org and I thought it was pretty cool and I wanted to show it to you this was a challenge called registry part of the CTF Zone finals for the 2024 game and credit where credit is due this is all put together by keltech from the team uh cat but sad I think in some Le speak there I want to make sure all the credit goes to them this is their work this is their write up this is their experience in the capture the flag competition and this challenge I did not play but I genuinely think this is kind of a cool thing to Showcase so I'd like to walk through it and maybe do a little bit of demo if we can recreate a part of the challenge the overview here though is that they were given an attack and defense challenge containing five different Serv…