My CTF Challenges
This is some challenges I created for CTF competitions.
TSJ CTF 2022
It is recommended to read Crypto writeups here, because it supports math rendering. 2022/05/22: GitHub supports MathJax rendering on GitHub now, but it still have some compatibility issues, so you might still want to use the url above when having issues.
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Futago | Crypto, CSC | RSA | โ |
| RNG++ | Crypto | LCG | โ โ |
| babyRSA | Crypto | RSA, ECC | โ โ |
| Top Secret | Crypto | GF, dlog | โ โ โ |
| Cipher Switching Service | Crypto | RSA, ElGamal | โ โ โ |
| Signature | Crypto | ECDSA, LLL, AES-CTR | โ โ โ |
| RNG+++ | Crypto | LCG, LLL | โ โ โ โ |
| Nim Notes | Web | Script Gadgets, CSRF, CRLF Injection, CSP | โ โ โ โ |
| Genie [1] | Web, Crypto | Path traversal, AES-CBC, Deserialization | โ โ โ โ |
| Just a pyjail | Misc | Pyjail | โ โ โ |
[1]: This challenge is made by both @splitline and me.
HITCON CTF 2022
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| BabySSS | Crypto | SSS, CRT | โ โ |
| Superprime | Crypto | Binary Search, Prune and Search | โ โ โ |
| Chimera | Crypto | ECM, LLL/Coppersmith, ECDLP, Hidden Subset Sum | โ โ โ โ |
| LemMinX | Misc | LSP, XXE | โ โ โ |
| Secure Paste | Web, Crypto | JSONP, Cipher Suite Confusion, DOMPurify, CSP | โ โ โ โ |
HITCON CTF 2023
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Share | Crypto | SSS, CRT | โ โ |
| EZRSA | Crypto | ECC, Wiener, ECM | โ โ โ |
| Echo | Crypto | RSA, Index Calculus, LLL | โ โ โ |
| Random Shuffling Algorithm | Crypto | Noisy CRT, Coppersmith | โ โ โ โ |
| Collision | Crypto | Code Review, Python Hash Collision | โ โ โ โ |
| Lisp.js | Misc | Node.js Jail | โ โ โ |
| Login System | Web | TE.TE, JSON Injection, YAML | โ โ โ |
| Canvas | Web | JS Jail, Worker, CSP | โ โ โ โ |
| Harmony | Web | Electron | โ โ โ โ โ |
ImaginaryCTF 2023
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Tan | Crypto | LLL | โ โ |
| Wasteful | Crypto | RSA, Coppersmith | โ โ |
| Sus | Crypto | RSA, Math | โ โ โ |
| Imaginary Casino | Crypto | CSIDH, RNG | โ โ โ |
| Login | Web | PHP | โ โ |
| Sanitized | Web | DOMPurify, XHTML | โ โ โ |
| Sanitized Revenge | Web | DOMPurify, XHTML | โ โ โ |
| Typechecker | Reverse | TypeScript, Math | โ โ |
| Get and set | Misc | Pyjail | โ โ |
ImaginaryCTF
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Really Simple Algorithm | Crypto | RSA, Continued Fractions | โ โ |
| Minimal | Pwn | Stack pivoting, read(2) return value, SROP | โ โ |
These two challenges are created before I became a board of ImaginaryCTF.
Round 26
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Box | Crypto | Affine function | โ |
| pqqp | Crypto | RSA, Number Theory | โ |
| First RSA | Crypto | RSA | โ โ |
| No modulus | Crypto | RSA, LLL | โ โ โ |
| Login Please | Web | JavaScript, Prototype | โ |
| Read | Pwn | Shellcoding | โ โ |
| Not a kernel pwn | Misc | Privilege Escalation | โ โ |
| Free Shell | Misc | Bash | โ โ |
| Here's some Rev v2 | Reverse | Pyc | โ |
| Here's some Rev v3 | Reverse | LCG | โ |
Round 27
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| RSA-CBC | Crypto | RSA | โ |
| RSA-CBC v2 | Crypto | RSA, Coppersmith | โ โ |
| Mobius | Crypto | Rational Function, LLL | โ โ โ |
| Hello World as a Service | Misc | Java, Quirks | โ โ |
| Baby Shell | Pwn | C++, std::string_view, UAF | โ |
Round 28
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Substitution | Crypto | RSA, Search | โ โ |
| Unchanged | Reverse | pthread, LCG | โ โ |
| Filter Master | Web | PHP, filter | โ โ |
| Half FFT | Misc | FFT, LLL | โ โ โ |
Round 29
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Strong Prime | Crypto | DLP, CRT | โ โ |
| Web3 | Crypto | Ethereum, ECDLP | โ โ |
| Req Bin | Web | Python Format String, Flask | โ โ |
| Generic Flag Checker | Reverse | Signal Handler | โ โ |
| xkcd 835 | Pwn | UAF | โ โ |
Round 30
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| PowerRSA | Crypto | RSA | โ |
| Easy DSA: LCG | Crypto | ECDSA, LCG, LLL | โ โ โ |
| Fake Flags | Web | Trolling | โ |
| Echo | Web | Request Smuggling | โ โ |
Round 31
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| KVIN | Web/Misc | JavaScript | โ โ |
Round 32
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Poly RSA | Crypto | RSA, GCD | โ โ |
| Old School | Web | Bash, CGI | โ โ |
Round 33
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Vault | Web | XSS, Cache | โ โ โ |
Round 34
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Integrity | Crypto | CRT-RSA, Coppersmith | โ โ |
Round 35
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Encrypted Command Executor | Crypto | ECB | โ |
Round 37
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| You can't reverse me | Misc/Reverse | Hook | โ โ |
AIS3 Pre-exam 2022
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| JeetQode | Misc | PPC, JQ | โ โ |
| B64DLE | Misc | AES-CTR, Pickle, Python Format String | โ โ โ |
| SC | Crypto | Classic | โ |
| Fast Cipher | Crypto | Modular Arithmetic | โ |
| shamiko | Crypto | SHA1 Collision, DSA | โ โ |
| Really Strange orAcle | Crypto | GCD, Binomial Theorem | โ โ |
| pettan | Crypto | RSA Small Message, MT19937, Related Message | โ โ โ |
| pekobot | Crypto | Invalid Curve Attack | โ โ โ |
| Flag Checker | Reverse | ROP, Pickle, Single Prime RSA | โ โ |
| Private Browsing | Web | SSRF, Redis, PHP Deserialization | โ โ |
| UTF-8 Editor | Pwn | C++, std::vector, OOB, GOT overwrite | โ โ |
| SAAS | Pwn | C++, Copy Constructor, UAF | โ โ โ |
AIS3 Pre-exam 2023
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| ECC | Crypto | ECC | โ |
| Not Wiener | Crypto | RSA, Coppersmith | โ โ |
| Media Server | Misc | Python http, procfs | โ โ |
| Gitly | Web | 0day | โ |
| Password Generator | Pwn | Math, ROP | โ โ |
AIS3 EOF 2023 - koh-jeopardy
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| Shamiko no fukushuu | Crypto | ECDSA, Hmac collision | โ |
| onelinecrypto | Crypto | RSA, LSB | โ |
| NotLFSR | Crypto | LFSR | โ โ |
| magicRSA | Crypto | RSA | โ โ |
| Neo RSA | Crypto | RSA, coppersmith | โ โ |
Security BSides Ahmedabad CTF 2022
| Name | Category | Tags | Difficulty |
|---|---|---|---|
| A complex number | Crypto | LLL | โ โ โ |