CVE-2007-0900 in Tagboard
Summary
by MITRE
Multiple PHP remote file inclusion vulnerabilities in TagIt! Tagboard 2.1.B Build 2 and earlier, when register_globals is enabled, allow remote attackers to execute arbitrary PHP code via a URL in the (1) configpath parameter to (a) tagviewer.php, (b) tag_process.php, and (c) CONFIG/errmsg.inc.php; and (d) addTagmin.php, (e) ban_watch.php, (f) delTagmin.php, (g) delTag.php, (h) editTagmin.php, (i) editTag.php, (j) manageTagmins.php, and (k) verify.php in tagmin/; the (2) adminpath parameter to (l) tagviewer.php, (m) tag_process.php, and (n) tagmin/index.php; and the (3) admin parameter to (o) readconf.php, (p) updateconf.php, (q) updatefilter.php, and (r) wordfilter.php in tagmin/; different vectors than CVE-2006-5249.
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Analysis
by VulDB Data Team • 08/10/2022
The vulnerability described in CVE-2007-0900 represents a critical remote file inclusion flaw in TagIt! Tagboard version 2.1.B Build 2 and earlier, which operates under specific dangerous conditions that enable arbitrary code execution. This vulnerability exists within the PHP application's handling of user-supplied input parameters, specifically targeting multiple entry points that process configuration and administrative paths. The flaw becomes exploitable when the PHP configuration option register_globals is enabled, a dangerous setting that automatically creates global variables from HTTP request data, fundamentally compromising application security boundaries. The vulnerability affects a wide range of files including tagviewer.php, tag_process.php, and various administrative scripts within the tagmin directory, creating multiple attack vectors that collectively amplify the threat surface.
The technical exploitation mechanism leverages the insecure handling of URL parameters that are directly incorporated into file inclusion functions without proper validation or sanitization. Attackers can craft malicious URLs containing specially formatted paths that, when processed by the vulnerable application, result in the inclusion and execution of arbitrary PHP code from remote servers. This occurs because the application concatenates user-provided input directly into include or require statements, creating a classic remote file inclusion vulnerability classified under CWE-88. The specific parameters affected include configpath, adminpath, and admin, each pointing to different script execution paths that collectively enable attackers to achieve code execution. The vulnerability's impact extends beyond simple code inclusion as it allows full system compromise when combined with the dangerous register_globals configuration, enabling attackers to execute malicious payloads with the privileges of the web server process.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected web server and potentially the entire underlying system. An attacker can upload and execute malicious PHP code, establish backdoors, steal sensitive data, modify application behavior, or use the compromised server as a launch point for further attacks against internal networks. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous for widespread deployment. The fact that multiple files across different directories are affected means that the attack surface is extensive, and the vulnerability can be exploited through various application workflows. This type of vulnerability falls under the ATT&CK technique T1190 for exploitation of remote services and T1059 for command and scripting interpreter usage, demonstrating how remote file inclusion can lead to complete system compromise.
Mitigation strategies for this vulnerability must address both the immediate application-level fixes and the underlying dangerous configuration that enables exploitation. The primary recommendation is to disable the register_globals PHP configuration option immediately, as this setting fundamentally undermines security boundaries and makes the application vulnerable to numerous attack vectors. Application-level patches should implement proper input validation and sanitization for all user-supplied parameters, particularly those used in file inclusion operations. The code should be modified to use whitelisting approaches for path validation, implement strict file inclusion checks, and avoid direct concatenation of user input into include statements. Additionally, implementing proper access controls and authentication mechanisms within the tagmin directory structure would limit the exposure of administrative functions. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts, while conducting regular security assessments to identify and remediate similar vulnerabilities in other applications. The vulnerability demonstrates the critical importance of secure coding practices and the dangers of legacy PHP configurations that were once common but are now recognized as security risks.