Skip to content

Mysterious Learnings

Description

One day the archeologist came across a strange metal plate covered in uncommon hieroglyphics. It looked like blueprints for some kind of alien technology. "What kind of magic is this?" He studied the plate more closely and was amazed by the advanced technology and incredible engineering they were using at a time like this. This could only lead him in him wanting to learn more...

Solution

Challenge looks similar to previous years Cyber Apocalypse, even with the same filename alien.h5 but doesn't come with any training data.

First tried to open the model with Panoply but didn't find much, can also use python.

import h5py
from tensorflow.keras.models import model_from_json

filename = 'alien.h5'
with h5py.File(filename, 'r') as f:
    model_weights_attrs = dict(f['model_weights'].attrs)
    model_architecture = f.attrs['model_config']

model = model_from_json(model_architecture)
model.load_weights(filename)

print("Layers in the model:")
print("=====================")
model.summary()

SFRCe24wdF9zb
Layers in the model:
=====================
Model: "19oNHJkX3RvX3V"
_________________________________________________________________
 Layer (type)                Output Shape              Param #
=================================================================
 conv2d_3 (Conv2D)           (None, 30, 30, 32)        896

 max_pooling2d_2 (MaxPooling  (None, 15, 15, 32)       0
 2D)

 conv2d_4 (Conv2D)           (None, 13, 13, 64)        18496

 max_pooling2d_3 (MaxPooling  (None, 6, 6, 64)         0
 2D)

 conv2d_5 (Conv2D)           (None, 4, 4, 64)          36928

 uZDNyc3Q0bmR9 (Lambda)      (None, 4, 4, 64)          0

 flatten_1 (Flatten)         (None, 1024)              0

 dense_2 (Dense)             (None, 64)                65600

 dense_3 (Dense)             (None, 10)                650

 lambda_1 (Lambda)           (None, 10)                0

=================================================================
Total params: 122,570
Trainable params: 122,570
Non-trainable params: 0

Added the base64-y looking strings together: SFRCe24wdF9zb19oNHJkX3RvX3VuZDNyc3Q0bmR9 and convert with CyberChef

Flag: HTB{n0t_so_h4rd_to_und3rst4nd}