webmedium

Calculator

hackerlab

Task: Calculator web app with Go backend exposing /source endpoint. Solution: Discovered obfuscated 'file' parameter (byte array), exploited LFI to read /proc/self/environ and extract flag from environment variables.

$ ls tags/ techniques/

lfi path_traversal proc_filesystem environment_variables source_code_analysis local_file_inclusion go golang byte_array_obfuscation

Local File Inclusion via hidden parameterReading /proc/self/environ for environment variablesDecoding obfuscated Go byte arrays

Analysis

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

$ python3 exploit.py --target 192.168.1.1 --port 8080
[*] Connecting to target...
[+] Shell obtained!

Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

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