CVE-2008-5186 in geshi
Summary
by MITRE
** DISPUTED ** The set_language_path function in geshi.php in Generic Syntax Highlighter (GeSHi) before 1.0.8.1 might allow remote attackers to conduct file inclusion attacks via crafted inputs that influence the default language path ($path variable). NOTE: this issue has been disputed by a vendor, stating that only a static value is used, so this is not a vulnerability in GeSHi. Separate CVE identifiers would be created for web applications that integrate GeSHi in a way that allows control of the default language path.
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability identified as CVE-2008-5186 pertains to the Generic Syntax Highlighter (GeSHi) library, specifically targeting the set_language_path function within the geshi.php file. This issue was flagged as potentially allowing remote attackers to execute file inclusion attacks through manipulated inputs that affect the default language path variable. The vulnerability represents a classic case of insecure direct object reference where user-controllable parameters could influence the path resolution mechanism. According to the vendor's assessment, the vulnerability has been disputed because only static values are used within the GeSHi library itself, suggesting that the core library does not inherently expose this risk. However, the security community recognizes that the vulnerability could manifest when web applications integrate GeSHi in ways that permit external control over the default language path parameter, creating an attack surface that extends beyond the library's native functionality.
The technical flaw manifests in how the set_language_path function processes the $path variable, which could be influenced by external inputs. When an application incorporates GeSHi without proper input validation or sanitization, attackers might manipulate the language path parameter to include malicious file paths. This type of vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The function's behavior suggests that it may concatenate user-provided input directly into file path operations without adequate validation, creating an opportunity for attackers to reference arbitrary files on the server. The attack vector typically involves crafting malicious input that gets processed by the vulnerable function, potentially leading to unauthorized file access or inclusion of malicious content.
The operational impact of this vulnerability, while disputed by the vendor for the core library, remains significant for web applications that improperly integrate GeSHi. When applications fail to validate or sanitize the language path parameter before passing it to GeSHi, attackers could exploit this weakness to access sensitive files, execute arbitrary code, or perform other malicious activities. The vulnerability's severity depends heavily on how the library is integrated within the application architecture, making it a potential vector for more serious attacks such as remote code execution or data exfiltration. Organizations using GeSHi in web applications must understand that the vulnerability's exploitation potential is not inherent to the library itself but rather emerges from improper application integration practices. The attack could potentially allow adversaries to escalate privileges or gain unauthorized access to system resources, particularly when the application runs with elevated permissions.
Mitigation strategies for this vulnerability require a multi-layered approach focused on both application-level defenses and proper integration practices. The primary recommendation involves implementing strict input validation and sanitization for any parameters that influence the language path in GeSHi integration. Applications should avoid directly using user-controllable data in path resolution functions, instead employing whitelisting mechanisms or predefined safe paths. Security controls should include input filtering to prevent path traversal sequences and ensure that all file paths are validated against a known set of acceptable values. Organizations should also consider implementing proper access controls and privilege separation to limit the potential impact of any successful exploitation attempts. Additionally, regular security assessments and code reviews should be conducted to identify improper integration patterns that could expose the application to similar vulnerabilities, particularly those related to CWE-22 and ATT&CK technique T1059.007 for remote code execution through file inclusion mechanisms.