CVE-2008-0559 in Nilsons Blogger
Summary
by MITRE
Multiple directory traversal vulnerabilities in Nilson s Blogger 0.11 allow remote attackers to include and execute arbitrary local files via a .. (dot dot) in (1) the permalink parameter in core.php, accessed through index.php; and (2) the thispost parameter in comments.php.
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Analysis
by VulDB Data Team • 08/14/2025
The vulnerability identified as CVE-2008-0559 represents a critical directory traversal flaw affecting Nilson s Blogger version 0.11, exposing the application to remote code execution through improper input validation. This weakness stems from inadequate sanitization of user-supplied parameters that are directly incorporated into file system operations without proper validation or encoding. The vulnerability manifests in two distinct attack vectors within the application's core functionality, both of which leverage the .. (dot dot) sequence to manipulate file paths and access restricted system resources.
The technical implementation of this vulnerability occurs through two primary attack surfaces within the application's codebase. The first vector involves the permalink parameter in core.php, which is accessed through index.php and allows attackers to manipulate file inclusion paths by injecting directory traversal sequences. The second vector targets the thispost parameter in comments.php, where similar path manipulation techniques can be employed to access arbitrary local files. Both attack vectors demonstrate the classic characteristics of directory traversal vulnerabilities, which are categorized under CWE-22 in the Common Weakness Enumeration framework. These flaws represent a fundamental failure in input validation and output encoding, where user-controllable data is directly used in file system operations without proper sanitization.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it enables remote attackers to execute arbitrary code on the affected system. An attacker can leverage these traversal sequences to include system files such as configuration files, database credentials, or even system binaries, potentially leading to complete system compromise. The attack requires no authentication and can be executed remotely, making it particularly dangerous for web applications that are publicly accessible. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as it allows attackers to execute arbitrary commands through file inclusion mechanisms. The implications are severe for any system running the vulnerable software, as successful exploitation could result in data breaches, system takeover, or further lateral movement within a network infrastructure.
Mitigation strategies for this vulnerability must address the root cause through comprehensive input validation and proper file path handling. The most effective remediation involves implementing strict parameter validation that rejects or encodes any directory traversal sequences before they are processed by the application. Developers should employ whitelisting approaches for file access operations, ensuring that only predetermined, safe file paths are accessible. Additionally, the application should implement proper access controls and file system permissions to limit what files can be accessed even if traversal attempts are successful. Security headers and application firewalls can provide additional layers of protection, though the fundamental fix requires code-level changes to prevent the inclusion of user-controllable data in file system operations. Organizations should also implement regular security testing including dynamic application security testing and static code analysis to identify similar vulnerabilities in other applications and prevent exploitation attempts.