Linux & permissionsmedium150 pts0 solves

Permission Audit

You received an excerpt of a Linux server's file system as a tarball. One misconfigured script lets an unprivileged user escalate to root through a scheduled job.

Learning objectives

Read Unix permissions and cron configuration to find a privilege-escalation path.

Instructions

Inspect rootfs-excerpt.tar.gz without extracting as root. Find the world-writable script executed by a root cron job; the flag is in its header comments. Beware of decoys.

Prerequisites: Unix permissions (rwx), cron syntax.

Flag format: cspk{...}

Files: rootfs-excerpt.tar.gz (0.6 KB) (download after registering)

Useful tools: Lynis

References

Linux man-pages — cron(8) / crontab(5)
Lynis auditing tool

Write-up

The full write-up and learning takeaways unlock after you solve this challenge — spoilers stay hidden until then.