CVE-2005-2805 in e107
Summary
by MITRE
forum_post.php in e107 0.6 allows remote attackers to post to non-existent forums by modifying the forum number.
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Analysis
by VulDB Data Team • 07/05/2021
The vulnerability described in CVE-2005-2805 affects the e107 content management system version 0.6, specifically within the forum_post.php script. This represents a classic access control flaw that undermines the integrity of the forum's permission structure and allows unauthorized users to post content to forums they should not have access to. The vulnerability stems from inadequate input validation and insufficient authorization checks within the forum posting mechanism, creating a pathway for malicious actors to manipulate the system's behavior through simple parameter modification.
The technical exploitation of this vulnerability occurs through the manipulation of the forum number parameter that is typically passed to the forum_post.php script. When an attacker modifies this parameter to reference a non-existent forum identifier, the system fails to properly validate whether the user has legitimate access rights to post in that particular forum. This flaw falls under the category of improper input validation as defined by CWE-20, where the application does not adequately sanitize or validate user-supplied data before processing it. The vulnerability essentially allows for privilege escalation through parameter tampering, enabling attackers to bypass normal forum access controls and potentially post content to restricted areas of the discussion system.
The operational impact of this vulnerability extends beyond simple unauthorized posting, as it can lead to significant security and data integrity concerns within the e107 forum environment. Attackers could potentially flood restricted forums with spam content, post malicious links, or inject harmful content that might compromise other users or the overall system. This vulnerability also creates opportunities for information disclosure, as attackers might gain access to forums containing sensitive discussions or restricted information. The flaw could be leveraged as part of a broader attack strategy to establish persistence or to create confusion within the forum's user base. From an attacker's perspective, this represents a low-effort method for gaining unauthorized access to restricted forum functionality, aligning with ATT&CK technique T1078 for valid accounts and T1566 for social engineering through compromised forum access.
The root cause of this vulnerability lies in the absence of proper access control validation within the forum_post.php script. The system should implement robust authentication checks that verify both the user's legitimacy and their authorization level before allowing any posting activity. Effective mitigations should include implementing proper input validation that sanitizes all user-supplied parameters, enforcing strict access control policies that validate forum membership and permissions before allowing post operations, and implementing proper session management to ensure that only authenticated users can perform posting actions. Additionally, the system should maintain audit logs of all forum posting activities to detect and respond to unauthorized access attempts. Organizations should also consider implementing web application firewalls and input filtering mechanisms to prevent parameter tampering attacks. The vulnerability demonstrates the critical importance of defense in depth strategies and proper access control implementation, as outlined in security standards such as NIST SP 800-53 and ISO/IEC 27001, which emphasize the need for proper authorization controls and input validation in web applications.