Source: cve@mitre.org
MyBB (aka MyBulletinBoard) before 1.4.12 does not properly handle a configuration with a visible forum that contains hidden threads, which allows remote attackers to obtain sensitive information by reading the Latest Threads block of the Portal Page.
MyBB versions prior to 1.4.12 are vulnerable to an information disclosure flaw. This vulnerability allows attackers to read hidden thread titles from the Latest Threads block on the portal page, potentially revealing sensitive information and facilitating further attacks. Successful exploitation can lead to compromise of confidential data and escalation of privilege.
Step 1: Configuration: An administrator configures a MyBB forum to be visible to all users but creates threads within that forum with restricted visibility (e.g., only visible to moderators or specific user groups).
Step 2: Portal Access: An unauthenticated or low-privilege user accesses the MyBB portal page.
Step 3: Latest Threads Block: The portal page renders the 'Latest Threads' block, which is designed to display recent thread titles.
Step 4: Information Leakage: Due to the vulnerability, the 'Latest Threads' block displays the titles of the hidden threads, even though the user does not have permission to view the full threads.
Step 5: Information Gathering: The attacker gathers information about the hidden threads, such as their titles and potentially their authors, which can be used to plan further attacks or identify sensitive information.
The vulnerability stems from an improper access control mechanism within MyBB's portal page rendering logic. Specifically, the code responsible for displaying the 'Latest Threads' block fails to adequately filter hidden threads when a forum is configured to be visible but contains threads with restricted visibility. The core issue lies in the lack of proper checks to ensure that the user has the necessary permissions to view the threads before displaying their titles in the portal's summary. This allows unauthorized access to thread titles, which can be used to glean information about the forum's content and potentially identify further vulnerabilities or sensitive data.
While no specific APT groups are directly linked to this CVE, the nature of the vulnerability makes it attractive to various threat actors. The information disclosure could be a precursor to more sophisticated attacks. CISA KEV status: Not Listed
Monitor web server logs for unusual access patterns to the MyBB portal page, especially from unauthenticated users.
Analyze HTTP responses for the 'Latest Threads' block. Look for thread titles that should not be visible based on user permissions.
Implement file integrity monitoring on MyBB core files to detect unauthorized modifications.
Network traffic analysis: Examine HTTP requests and responses for the portal page, looking for suspicious patterns or data exfiltration attempts related to thread titles.
Upgrade to MyBB version 1.4.12 or later.
Implement strict access control policies to ensure that users only have access to the resources they are authorized to view.
Regularly audit user permissions and forum configurations.
Apply the principle of least privilege.
Implement a Web Application Firewall (WAF) to filter malicious requests.
Regularly scan the MyBB installation for vulnerabilities.