Web exploitation
Find and chain vulnerabilities in web applications — the most common attack surface in production today.
SQLiXSSSSRFIDOR
Capture the flag · Legal & sandboxed
Break things on purpose. Legally.
Hack4Shell is a CTF platform where you exploit real vulnerability classes — web, crypto, pwn, reverse engineering, forensics, OSINT — inside isolated labs built for exactly that.
6challenge categories
3difficulty tiers
24/7isolated lab access
$ connect --lab web-101
[+] instance provisioned
web-101 -$ ls -la /
web-101 -$ flag.txt README.md
web-101 -$ cat /README.md
Flag format is H4S-CTF{...}
web-101 -$ cat /flag.txt
H4S-CTF{d3m0_fL@g_f0rm@t_8932}
$
// what's a ctf
Vulnerable by design, safe by construction
A Capture The Flag competition hides short text strings — flags — inside programs and web apps built specifically to contain a bug. You find the bug, exploit it, and the flag proves you did.
That distinction matters. The skill is identical to what's used in professional penetration testing and bug bounty work — reconnaissance, exploitation, privilege escalation, reporting.
Why it works
Reading about a bug and exploiting one are different skills
CTFs close that gap. Here's what practicing on real, contained vulnerabilities builds that theory alone doesn't.
Methodology, not memorization
Each flag forces recon, hypothesis, and testing — the same loop used in real assessments, not a checklist of memorized payloads.
Bug-bounty rehearsal
Web and OSINT tracks mirror how a real bounty engagement starts — enumerate, probe, chain — before you touch an in-scope target.
Defense through offense
Understanding how a bug is exploited is the fastest route to knowing how to close it — offense and defense are one discipline here.
Challenge categories
Six domains, one skill: finding what shouldn't be findable
Cryptography
Break weak schemes, exploit implementation flaws, and recover plaintext that was never supposed to come back.
RSAHashingSteganography
Reverse engineering
Read a binary the way its author never intended you to — disassemble, debug, and rebuild its logic in your head.
GhidraGDBx64dbg
Binary exploitation
Corrupt memory on purpose. Bypass modern mitigations and turn a bug into arbitrary code execution.
Buffer overflowHeapASLR bypass
Digital forensics
Reconstruct an intrusion after the fact from memory dumps, disk images, and packet captures.
Memory analysisPCAPDisk images
OSINT
Pull scattered public data into a coherent picture — the reconnaissance phase of every real engagement.
ReconMetadataSocial footprint
Learning path
A track that actually goes somewhere
$ tier --set beginner
Beginner — get comfortable in the terminal
HTTP requests, Base64 and hex encoding, basic Linux navigation, netcat and curl. No prior exploitation experience assumed.
$ tier --set intermediate
Intermediate — combine techniques
Chain two or three weaknesses together, write small scripts to automate recon, and start reading source code for logic flaws.
$ tier --set advanced
Advanced — build your own exploits
Bypass modern mitigations, research unfamiliar vulnerability classes on the fly, and write exploits with no public reference to copy.
FAQ
Questions worth answering directly
Is hacking on Hack4Shell legal?+
Yes. Every target runs in an isolated, disposable lab you're explicitly authorized to attack. The techniques are identical to what's illegal against a system you don't own — the difference is authorization, which is built into the platform.
Do I need programming experience to start?+
No. Beginner challenges only assume basic command-line comfort. Scripting ability grows naturally as you move into the intermediate and advanced tiers.
How does this help with bug bounty work?+
The web and OSINT tracks rehearse the same recon-then-exploit methodology used in real bounty programs, so you arrive at an in-scope target with practiced instincts rather than a blank page.
Your next flag is waiting
Spin up an isolated lab and start with a beginner web challenge — no setup beyond an account.
Create free account →