CVE-2017-5609 in Serendipity
Summary
by MITRE
SQL injection vulnerability in include/functions_entries.inc.php in Serendipity 2.0.5 allows remote authenticated users to execute arbitrary SQL commands via the cat parameter.
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Analysis
by VulDB Data Team • 05/16/2026
The CVE-2017-5609 vulnerability represents a critical sql injection flaw within the Serendipity blogging platform version 2.0.5, specifically within the include/functions_entries.inc.php file. This vulnerability affects the category parameter handling mechanism that processes user input for filtering blog entries by category. The flaw stems from insufficient input validation and sanitization of the cat parameter, which is processed without proper escaping or parameterization techniques before being incorporated into sql queries. Attackers exploiting this vulnerability can manipulate the cat parameter to inject malicious sql commands that bypass authentication checks and execute arbitrary database operations. The vulnerability requires authentication as a prerequisite, meaning only users with valid accounts can exploit this weakness, though it still poses significant risk to system integrity and data confidentiality.
The technical implementation of this vulnerability aligns with common sql injection patterns categorized under CWE-89, which specifically addresses improper neutralization of special elements used in sql commands. The flaw occurs when user-supplied data flows directly into sql query construction without appropriate sanitization measures, creating an environment where malicious input can alter the intended query execution path. The cat parameter in the functions_entries.inc.php file serves as the injection vector, where attackers can craft payloads that manipulate the sql statement structure to extract sensitive information, modify database records, or even gain unauthorized access to administrative functions. This type of vulnerability falls under the ATT&CK technique T1071.004, which covers application layer protocol manipulation, specifically targeting web application sql injection vulnerabilities.
The operational impact of CVE-2017-5609 extends beyond simple data theft, as authenticated attackers can leverage this weakness to escalate privileges and potentially compromise the entire blogging platform. Database operations such as data modification, deletion, or extraction become possible through carefully crafted sql injection payloads targeting the cat parameter. The vulnerability affects the integrity and confidentiality of the entire blog system, potentially exposing user credentials, blog content, and underlying database structure to unauthorized access. Given that this is a remote authenticated vulnerability, attackers do not need physical access to the system but can exploit it through network-based attacks. The platform's security posture is significantly weakened as the vulnerability allows for persistent access to the database through the compromised user account, potentially enabling further lateral movement within the network infrastructure.
Mitigation strategies for CVE-2017-5609 should prioritize immediate patching of the Serendipity 2.0.5 platform to the latest stable release containing the sql injection fix. System administrators should implement proper input validation and parameterized queries throughout the application codebase to prevent similar vulnerabilities from occurring in other components. The implementation of web application firewalls and sql injection detection mechanisms can provide additional layers of protection against exploitation attempts. Regular security audits and code reviews should focus on input handling mechanisms, particularly parameters used in database queries, to identify and remediate potential injection points. Organizations should also consider implementing principle of least privilege access controls, ensuring that authenticated users have only the minimum necessary permissions to perform their required functions. Network segmentation and monitoring solutions can help detect unusual database access patterns that may indicate exploitation attempts, while regular security training for administrators can improve overall incident response capabilities and vulnerability awareness.