Challenge list
CryptographyLevel 2★★☆☆☆AES-ECB Mode Weakness
ECB leaks repeated block patterns. This introductory task first checks the difference between encryption and encoding.…
Digital ForensicsLevel 2★★☆☆☆Find Attack in Apache Logs
Analyze the Apache access.log (common format) to find traces of SQL injection. Tell which attacks succeeded and which…
Digital ForensicsLevel 2★★☆☆☆Flag Hidden in Excel Macro
Analyze the macro code embedded in the Excel workbook and find the hidden authentication code (the flag). Learn how to…
Digital ForensicsLevel 2★★☆☆☆Hidden PDF Streams
The PDF file contains compressed object streams. An internal note that is not shown on the page is hidden inside them.…
CryptographyLevel 2★★☆☆☆RC4 Stream Cipher Weakness
RC4 was once widely used but is now deprecated. This introductory task focuses on recognizing the provided data…
CryptographyLevel 2★★☆☆☆Vigenere Cipher Decryption
Decrypt a Vigenere cipher when the key length is known and retrieve the flag. Ciphertext:…
Digital ForensicsLevel 2★★☆☆☆Find USB History in Windows Registry
Analyze the SYSTEM file (a text model of the USBSTOR part of the registry hive) to identify the USB device that was…
Digital ForensicsLevel 2★★☆☆☆Find Secret File in Disk Image
Inspect the ext4 filesystem disk image `disk.img`, find the secret backup hidden in the filesystem, and recover the…
CryptographyLevel 2★★☆☆☆Finding Hash Collisions
MD5 collisions are practical. Hashes with broken collision resistance must not be used for security-sensitive…
CryptographyLevel 2★★☆☆☆Hash Length Extension Attack
Simple signatures such as hash(secret || message) can be vulnerable to length extension attacks with Merkle-Damgard…
Digital ForensicsLevel 2★★☆☆☆Find Password in Packet Capture
Clear-text HTTP traffic from a shop's internal network was captured. Among many requests, exactly one is the…
CryptographyLevel 2★★☆☆☆Padding Oracle Basics
Padding oracle attacks use error differences as a plaintext recovery signal. This introductory task decodes leaked…
Digital ForensicsLevel 2★★☆☆☆Identify Intrusion Time from File Timestamps
Analyze the modification times of the files in evidence/ to identify when the intrusion occurred and which hidden…
Digital ForensicsLevel 2★★☆☆☆Find Process in Memory Dump
memory.dump is a simplified text of memory-analysis output (pslist / psscan / cmdline). Find the suspicious process…
CryptographyLevel 2★★☆☆☆Rainbow Table Attack
Unsalted fast password hashes can often be reversed with precomputed lookup databases. Reverse the given MD5 hash. MD5…
CryptographyLevel 2★★☆☆☆One-Time Pad Key Reuse Attack
A one-time pad is safe only when the key is used once. Reusing the key lets known plaintext recover other plaintexts.…
CryptographyLevel 2★★☆☆☆Predictable Randomness
Pseudo-random output with a fixed seed is reproducible and must not be used for cryptographic secrets. Flag generation…
Digital ForensicsLevel 2★★☆☆☆Recover Deleted Files
Recover the deleted compressed file (ZIP) from the disk image and find the flag in the memo inside it. Learn how to…
CryptographyLevel 2★★☆☆☆Breaking Small RSA Keys
Factor a tiny RSA modulus, recover the private exponent, and decrypt a list of ciphertext values. Public key and…
CryptographyLevel 2★★☆☆☆Cryptanalysis - Breaking the Affine Cipher
ciphertext.txt is an English report encrypted with the affine cipher E(x) = (a*x + b) mod 26. Letter case is preserved…
Digital ForensicsLevel 2★★☆☆☆Message Hidden in Image LSB
Extract the message hidden in the LSB (Least Significant Bit) of a PNG file. Learn the basics of steganography…