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sudo sed

Offensive Lab · medium · live throwaway Linux box · 3 tiered hints

Your own disposable practice box. player may run /usr/bin/sed as root via sudo. Read /root/flag.txt and write it to /home/player/flag.

▶ Start this challenge

Nobody has solved this one yet — be the first clear on the leaderboard.

How it works

Press start and you get your own real, disposable Linux VM — in the browser terminal or over SSH. Work the task on a live system; tmpfs.tech grades your solution automatically against the actual machine state, then throws the box away. No install, free to try as a guest.

More Offensive Lab challenges

Authorized local-privilege-escalation wargames on a disposable box you own.

• Capture the flag via a SUID binaryeasy
• SUID base64 read-backeasy · in-browser
• SUID cpeasy
• SUID ddeasy
• SUID findeasy
• SUID headeasy
• SUID man pager escapeeasy · in-browser
• SUID sedeasy

See all Offensive Lab challenges →

FAQ

Is it free? Yes — play as a guest, no signup required to start.

Do I need to install anything? No. Everything runs in your browser, or connect over SSH if you prefer your own terminal.

How is it graded? Automatically and deterministically — your work is checked against the real state of the machine you worked on.