CVE-2009-4904 in oBlog
Summary
by MITRE
article.php in oBlog does not properly restrict comments, which allows remote attackers to cause a denial of service (blog spam) via a comment=new action.
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Analysis
by VulDB Data Team • 01/01/2018
The vulnerability identified as CVE-2009-4904 affects the oBlog content management system where the article.php script fails to implement proper comment validation and restriction mechanisms. This flaw resides in the comment handling functionality that processes user submissions through the comment=new action parameter, creating an avenue for malicious actors to exploit the system's lack of input sanitization and access control measures.
This vulnerability represents a classic case of insufficient input validation and inadequate access control, classified under CWE-20 as "Improper Input Validation" and CWE-89 as "Improper Limitation of a Pathname to a Restricted Directory." The flaw allows remote attackers to submit comments without proper authorization or validation, enabling them to flood the system with unwanted content. The issue manifests specifically when the system processes the comment=new action, which should typically require proper authentication or at least basic validation before accepting user submissions.
The operational impact of this vulnerability extends beyond simple spam generation to encompass potential denial of service conditions that can severely disrupt blog operations. Attackers can leverage this weakness to overwhelm the system with excessive comment submissions, consuming server resources and potentially making the blog inaccessible to legitimate users. This type of attack aligns with ATT&CK technique T1499.004 for "Network Denial of Service" and can be classified as a form of spamming attack that degrades system performance and availability.
From a security perspective, the vulnerability demonstrates poor defensive programming practices where the system assumes all user inputs are legitimate without proper verification. The lack of rate limiting, input sanitization, or authentication checks creates an environment where malicious actors can exploit the system's trust model. This weakness can be exploited to create a cascading effect where legitimate users experience degraded service quality, and the system may eventually become unresponsive due to resource exhaustion from the flood of unauthorized comments.
Effective mitigation strategies should include implementing proper input validation and sanitization for all comment submissions, establishing rate limiting mechanisms to prevent comment flooding, and enforcing authentication requirements for comment posting. The system should also implement proper access controls to ensure that only authorized users can submit comments, and should log all comment-related activities for monitoring purposes. Additionally, deploying web application firewalls and implementing proper error handling can help detect and prevent exploitation attempts. These measures align with defensive techniques outlined in the MITRE ATT&CK framework for protecting against similar vulnerabilities in web applications.