Challenge list
Digital ForensicsLevel 3★★★☆☆Decrypt Encrypted Disk
`/challenge/secret_disk.img` is a genuine LUKS2 container. Its data area holds a backup (a tar archive). The…
CryptographyLevel 3★★★☆☆Cryptanalysis - RSA Common Modulus Attack
Two systems reused the same RSA modulus n and only changed the public exponent. The ciphertexts c1 and c2 of the same…
CryptographyLevel 3★★★☆☆Cryptanalysis - Diffie-Hellman with a Small Prime
An old IoT device performed Diffie-Hellman key exchange with a prime p of only 36 bits. handshake.txt contains p, g, A…
Digital ForensicsLevel 3★★★☆☆Data Hidden in Audio File
`hidden.wav` hides a message encoded with on-off keying (OOK). Turn the tone on/off slots into bits and decode them to…
Digital ForensicsLevel 4★★★★☆Extract Secret Key from Android App
Extract a safe ZIP-formatted APK fixture (evidence/app.apk) and analyze the encrypted API secret recorded in its…
Digital ForensicsLevel 4★★★★☆Detect Unauthorized Access in CloudTrail Logs
Analyze the CloudTrail export `/challenge/cloudtrail.json` and trace the unauthorized use of a stolen access key and…
Digital ForensicsLevel 4★★★★☆Extract Secrets from Docker Image Layers
`/challenge/image/` is an unpacked `docker save` export (OCI layout). The layers are stored in `blobs/sha256/` as…
Digital ForensicsLevel 4★★★★☆Decrypt TLS-Encrypted HTTPS Traffic
In `~/evidence/` there is a capture `traffic.pcap` (libpcap format) of HTTPS traffic from a client PC, and the TLS key…
Network SecurityLevel 4★★★★☆Network Analysis - Rebuilding Chunked gzip HTTP from TCP
capture.pcap records two HTTP exchanges over one TCP connection. The server's segments are reordered and some are…
Network SecurityLevel 4★★★★☆Network Analysis - TCP Retransmission Covert Channel
capture.pcap contains TCP retransmissions with duplicate sequence numbers. Extract retransmissions whose payload…
Digital ForensicsLevel 4★★★★☆Extract Malware Payload from Memory
`/challenge/memstrings.txt` holds the strings extracted from the address space of a suspicious process, and the…
Digital ForensicsLevel 4★★★★☆Detect Hidden Kernel Module in Memory
From the memory of a Linux host suspected of an LKM rootkit infection, three sets of module information were…
Digital ForensicsLevel 4★★★★☆Decode Multi-Stage Steganography
Three stages of steganography are planted in `/challenge/cover.png` and `/challenge/notes.txt`. Each stage holds the…
Digital ForensicsLevel 4★★★★☆Recover Fragmented JPEG File
`/challenge/fragments/` holds 256-byte clusters (`clus_NNNN.bin`) recovered from the unallocated space of a memory…
CryptographyLevel 4★★★★☆Cryptanalysis - DSA Nonce Reuse Key Recovery
/challenge/signatures.json, created with fresh keys at every start, holds the DSA public parameters (p of 1024 bits, q…
CryptographyLevel 4★★★★☆Cryptanalysis - Wiener's Attack on RSA
An embedded-device team made the RSA private exponent d very small to speed up decryption. The public exponent e in…
CryptographyLevel 4★★★★☆Cryptanalysis - Recovering an LCG's Hidden Parameters
A service generated both session tokens and an encryption keystream from a linear congruential generator x_{k+1} =…
Digital ForensicsLevel 4★★★★☆Recover Damaged RAID5 Array
The RAID5 array `/dev/md0` (4 members) on the file server fs01 no longer assembles after the member sdd failed.…
Digital ForensicsLevel 4★★★★☆Reconstruct Attack Scenario from Multiple Logs
`/challenge/web.log`, `/challenge/auth.log` and `/challenge/db.log` record the same intrusion among a lot of…
Digital ForensicsLevel 5★★★★★Reconstruct Full APT Attack Stages
Four logs, `/challenge/edr_process.log`, `proxy_http.log`, `dns_queries.log` and `dlp_transfer.log`, hold an APT…
Digital ForensicsLevel 5★★★★★Crack BitLocker Encrypted Drive
Learn BitLocker recovery-key verification with a safe metadata fixture. bitlocker.img is not a real volume. Identify…
Digital ForensicsLevel 5★★★★★Extract Message Hidden in Bitcoin Transaction
The victim paid the ransom to the Bitcoin address `bc1qr4nsmw4r3pay7hzfx0d9cq3vkt8e6m5ljgs2ua`.…
Digital ForensicsLevel 5★★★★★Extract Secret Key from IoT Device Firmware
Analyze the update file `/home/ctfuser/evidence/firmware.bin` of the network camera KNC-CAM-2000 (do not connect to a…
Network SecurityLevel 5★★★★★Network Analysis - IPv4 Overlapping Fragment Reassembly
The UDP datagram with IPv4 ID 0xbeef in fragments.pcap contains overlapping fragments that overwrite earlier bytes.…