CVE-2008-1635 in Keep It Simple Guest Book
Summary
by MITRE
Directory traversal vulnerability in view_private.php in Keep It Simple Guest Book (KISGB) 5.0.0 and earlier allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the tmp_theme parameter. NOTE: 5.1.1 is also reportedly affected.
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Analysis
by VulDB Data Team • 10/20/2024
The directory traversal vulnerability identified in CVE-2008-1635 affects the Keep It Simple Guest Book (KISGB) version 5.0.0 and earlier, with reports indicating version 5.1.1 may also be impacted. This vulnerability resides within the view_private.php script and represents a classic path traversal flaw that enables remote attackers to access arbitrary local files on the server. The vulnerability specifically manifests when the tmp_theme parameter is manipulated with directory traversal sequences such as .. (dot dot), allowing attackers to bypass normal file access controls and potentially execute malicious code on the target system. This type of vulnerability falls under CWE-22, which categorizes path traversal attacks as a fundamental security weakness in web applications.
The technical exploitation of this vulnerability occurs when user input from the tmp_theme parameter is directly incorporated into file inclusion operations without proper sanitization or validation. Attackers can construct malicious URLs that include sequences like ../../etc/passwd or similar traversal patterns to access sensitive system files that should remain protected from unauthorized access. The flaw essentially allows an attacker to manipulate the file system path resolution mechanism, enabling them to navigate beyond the intended directory boundaries and potentially access configuration files, database credentials, or other sensitive resources stored on the server. This vulnerability directly impacts the principle of least privilege and can lead to complete system compromise if sensitive files are accessible through the web root.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable full system compromise. Remote attackers who successfully exploit this vulnerability can gain access to sensitive data stored within the guest book application, including user credentials, private messages, and potentially system-level information that could facilitate further attacks. The vulnerability can be exploited by any remote user without authentication, making it particularly dangerous as it provides an attack surface that requires no prior access to the system. This weakness can be leveraged to escalate privileges, access administrative functions, or extract database contents that may contain additional sensitive information. The attack vector is straightforward and the exploitation requires minimal technical skill, making it a preferred target for automated scanning tools and malicious actors.
Mitigation strategies for this vulnerability include immediate patching of the affected KISGB versions to the latest available releases that contain proper input validation and sanitization. The recommended approach involves implementing strict input validation for all user-supplied parameters, particularly those used in file inclusion operations. Security measures should include removing or disabling the vulnerable tmp_theme parameter functionality, implementing proper path normalization, and ensuring that all file access operations use whitelisted directories and filenames. Organizations should also consider implementing web application firewalls to detect and block malicious traversal attempts, and conduct regular security assessments to identify similar vulnerabilities in other applications. This vulnerability aligns with ATT&CK technique T1059 which involves executing commands through various interfaces, and T1083 which covers discovering files and directories, making it a critical concern for defensive security operations. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security design.