$ exiftool -iTXt:secret QfUhZZXf > secret_compressed.bin $ file secret_compressed.bin secret_compressed.bin: zlib compressed data
$ 7z x secret_payload Result: secret.txt $ cat secret.txt Congratulations! You've found the hidden flag:
<form method="GET" action="download.php"> <input type="text" name="file" placeholder="File name"> <input type="submit" value="Download"> </form> The parameter is file . Testing with some basic values:
$ binwalk QfUhZZXf 0 0x0 PNG image, 640 x 480, 8-bit/color RGBA, non-interlaced A PNG header at offset 0! Let’s verify: https- ranoz.gg file QfUhZZXf
Run binwalk and strings for deeper insight:
$ curl "https://ranoz.gg/download.php?file=download.php%3fsource" No luck.
| Path | Status | Size | Comments | |--------------------------|--------|------|----------| | / | 200 | 3 kB | Landing page – simple “Welcome to Ranoz”. | | /download.php | 200 | 2 kB | Likely the entry point for file retrieval. | | /static/ | 200 | 1 kB | Holds images, CSS. | | /assets/ | 403 | — | Forbidden – may contain secrets. | | /robots.txt | 200 | 71 B | Contains: Disallow: /admin/ | Only the robots.txt line above. No sitemap. 3. Analyzing the Download Endpoint Visiting https://ranoz.gg/download.php gives a tiny HTML form: $ exiftool -iTXt:secret QfUhZZXf > secret_compressed
PNG file: QfUhZZXf (640x480) Chunk tEXt (keyword=Comment, text=...) Chunk iTXt (keyword=secret, compression=deflate, text=...) The iTXt chunk named contains a compressed blob. Extract it with exiftool :
$ 7z l secret_payload ... 0 0 0 0 0 -rw-r--r-- 0 0 secret.txt Extract:
$ pngcheck -v QfUhZZXf Output (truncated for brevity): Let’s verify: Run binwalk and strings for deeper
$ zcat secret_compressed.bin > secret_payload secret_payload is a ( .7z ).
Next, we tried to locate the raw file through :
$ gobuster dir -u https://ranoz.gg/ -w /usr/share/wordlists/dirb/common.txt -x .bak,.old,.php~ -t 50 Result: download.php.bak returned a 2 kB file. <?php // Simple file downloader – DO NOT expose to the public! $allowed = ['QfUhZZXf', 'public.txt', 'welcome.html']; if (isset($_GET['file'])) $file = basename($_GET['file']); if (in_array($file, $allowed)) $path = __DIR__ . "/files/" . $file; if (file_exists($path)) header('Content-Type: application/octet-stream'); header('Content-Disposition: attachment; filename="'.$file.'"'); readfile($path); exit;