CVE-2009-1575 in Drupal
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Drupal 5.x before 5.17 and 6.x before 6.11, as used in vbDrupal before 5.17.0, allows remote attackers to inject arbitrary web script or HTML via crafted UTF-8 byte sequences before the Content-Type meta tag, which are treated as UTF-7 by Internet Explorer 6 and 7.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/03/2019
The vulnerability described in CVE-2009-1575 represents a sophisticated cross-site scripting flaw that specifically targets the handling of character encoding in web applications. This issue affects Drupal content management systems versions 5.x prior to 5.17 and 6.x prior to 6.11, along with the vbDrupal module which extends Drupal functionality. The vulnerability exploits a fundamental misunderstanding in how certain web browsers interpret character encoding, particularly when processing UTF-8 byte sequences that precede critical HTML meta tags. The flaw exists in the way web applications process and validate input data, creating a pathway for malicious actors to inject harmful scripts into web pages viewed by other users.
The technical mechanism behind this vulnerability involves the manipulation of UTF-8 encoding sequences that occur before the Content-Type meta tag in HTML documents. Internet Explorer 6 and 7 browsers, which were prevalent at the time of the vulnerability, incorrectly interpreted certain UTF-8 byte sequences as UTF-7 encoding, creating a parsing inconsistency that attackers could exploit. This misinterpretation allowed malicious actors to craft input data that would be rendered as executable scripts when processed by vulnerable browsers. The vulnerability specifically targets the input sanitization mechanisms within Drupal's content handling system, where user-supplied data was not properly validated against potential encoding-based attack vectors.
The operational impact of this vulnerability extends beyond simple script injection, as it enables attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious sites. The attack vector leverages the browser-specific behavior of IE6 and IE7, making it particularly dangerous in environments where these older browsers were still in use. The vulnerability's exploitation requires minimal user interaction, as simply viewing a page containing the malicious content would trigger the script execution. This makes it particularly effective for mass distribution attacks through forums, comment sections, or any user-contributed content areas within the Drupal platform.
Security professionals should note that this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications. The issue also relates to ATT&CK technique T1566, which covers the exploitation of vulnerabilities in web applications through the injection of malicious code. Organizations affected by this vulnerability should prioritize immediate patching of their Drupal installations, ensuring all systems are updated to versions 5.17 or 6.11 and beyond. Additional mitigations include implementing proper input validation at multiple layers, configuring web application firewalls to detect and block suspicious UTF-8 sequences, and educating users about the risks of visiting untrusted websites. The vulnerability underscores the critical importance of proper character encoding handling in web applications and demonstrates how browser-specific inconsistencies can create exploitable conditions in otherwise secure systems.