Solving Polarflag from PolarCTF 2025 Winter through directory scanning, source analysis, password cracking, an MD5 check bypass, and command injection.

Following a compromised Umami container's alert from a shell script to an ELF loader and Go payload, with notes on C2 communication, file uploads, and plugin execution.

Reinstalling a dedicated server with Debian 13 and Proxmox VE, restoring multipath iSCSI storage, and setting up NAT and port forwarding for its VMs.

Solving the 2025 Gujianshan Misc challenge Fruit by extracting an appended ZIP, identifying OurSecret steganography, and decoding fruit-themed dialogue to recover the flag.

Running Chinese and English blogs as two Typecho instances, synchronizing post IDs with a plugin, and adding language switching, sitemaps, hreflang, and shared views and comments.

Troubleshooting failed pings between DN42 nodes after combining DN42 and clearnet routes, using ip route get to spot the wrong source address and adjusting BIRD's krt_prefsrc.

Writeups for five challenges from the 2025 Yangcheng Cup preliminaries, including Godot reversing, SM4-OFB keystream reuse, data extraction, and Pickle deserialization.

Trying VRF to separate DN42 and clearnet routing on one VPS, with interface, WireGuard, and BIRD configuration and notes on access to services on the host.