CVE-2006-0070 in Drupal
Summary
by MITRE
** DISPUTED ** Drupal allows remote attackers to conduct cross-site scripting (XSS) attacks via an IMG tag with an unusual encoded Javascript function name, as demonstrated using variations of the alert() function. NOTE: a followup by the vendor suggests that the issue does not exist in 4.5.6 or 4.6.4 when "Filtered HTML" is enabled, and since "Full HTML" would not filter HTML by design, perhaps this should not be included in CVE.
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability identified as CVE-2006-0070 represents a disputed cross-site scripting flaw within the Drupal content management system that was initially reported to affect versions prior to 4.5.6 and 4.6.4. This issue specifically targeted the handling of HTML input through IMG tags containing encoded javascript function names, with the alert() function serving as a demonstrative example of the potential exploitation vector. The vulnerability was categorized under the broader class of XSS attacks that allow remote attackers to inject malicious scripts into web pages viewed by other users, potentially leading to session hijacking, data theft, or other malicious activities.
The technical flaw stems from inadequate input validation and sanitization within Drupal's HTML filtering mechanisms, particularly when processing IMG tags with unusual encoded javascript function names. The vulnerability exploited the fact that certain HTML encoding variations could bypass standard security filters, allowing attackers to inject javascript code that would execute in the context of other users' browsers. This type of vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications where untrusted data is improperly handled and executed within web browsers.
The operational impact of this vulnerability was significant within the Drupal ecosystem, as it could potentially allow attackers to compromise user sessions and execute arbitrary code on behalf of authenticated users. The issue was particularly concerning because it demonstrated how seemingly benign HTML elements like IMG tags could be weaponized through encoding techniques to bypass security controls. The exploitability was enhanced by the fact that the vulnerability could be demonstrated using common javascript functions, making it accessible to attackers with basic knowledge of web security concepts.
The vendor's subsequent clarification regarding this CVE entry indicates that the issue may not have been properly validated, as the vulnerability was reportedly mitigated in versions 4.5.6 and 4.6.4 when "Filtered HTML" was enabled. This clarification reflects the complexity of vulnerability assessment in content management systems where different input filtering levels can dramatically affect the exploitability of security flaws. The distinction between "Filtered HTML" and "Full HTML" modes demonstrates how security controls within web applications must be carefully configured to prevent such vulnerabilities, as "Full HTML" by design does not filter HTML elements and therefore would not provide the protective measures against XSS attacks that "Filtered HTML" would offer.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the T1059.007 technique for Command and Scripting Interpreter: JavaScript, which addresses how attackers can leverage javascript execution capabilities to compromise systems. The vulnerability also aligns with the broader category of web application security issues that require proper input validation, output encoding, and security configuration management to prevent exploitation. This case highlights the importance of thorough vulnerability validation and the need for security teams to understand the specific configurations and filtering mechanisms that may affect the exploitability of security flaws within web applications. The disputed nature of this CVE entry underscores the importance of vendor verification and community validation in the security assessment process, as initial vulnerability reports may not always accurately reflect the true scope or severity of security issues within software applications.