2025weight 33.89kalmarunionen

KalmarCTF 2025

4 challenges with 8 published community solutions between them. Solution links go to CTFtime’s task page, which aggregates every writeup for a challenge - individual blog posts rot, the aggregator does not.

Full task list on CTFtime

Web3

Reach data or functionality the application meant to keep from you - through its inputs, its tokens, or its trust in the client.

Solve it with:JWT decoder and signature verifier JWT alg=none bypass generator Web attack payload catalog JWT secret brute force Learn: Web attacks and session tokens

Ez ⛳ v3
146 pts3 writeups
- caddy
- web
Same technique in picoCTF: Client-side-again, dont-use-client-side, Irish-Name-Repo 3
G0tchaberg
278 pts2 writeups
- web
Same technique in picoCTF: Client-side-again, dont-use-client-side, Irish-Name-Repo 3
DNXSS-over-HTTPS
186 pts1 writeup
- web
Same technique in picoCTF: Client-side-again, dont-use-client-side, Irish-Name-Repo 3

Cryptography1

Recover a plaintext or a key from something that was supposed to protect it. In practice: identify the scheme, find the parameter the author got wrong, exploit it.

Solve it with:Cipher identifier and automatic decoder Vigenere cipher solver with automatic key recovery RSA decryption and attack runner Wiener’s attack on small RSA private exponents In-browser hash cracker with rule transforms Learn: Classical ciphers and frequency analysis Learn: RSA and the parameters that break it

basic sums
155 pts2 writeups
- crypto
Same technique in picoCTF: StegoRSA, Timestamped Secrets, AES-ABC

Web3

Ez ⛳ v3

G0tchaberg

DNXSS-over-HTTPS

Cryptography1

basic sums

Other 2025 events