Source: cve@mitre.org
The Webform module 5.x before 5.x-2.8 and 6.x before 6.x-2.8, a module for Drupal, does not prevent caching of a page that contains token placeholders for a default value, which allows remote attackers to read session variables via unspecified vectors.
Drupal's Webform module is vulnerable to a caching issue that allows attackers to read sensitive session data of other users. This flaw enables remote attackers to potentially steal user credentials and compromise accounts by exploiting the module's failure to properly handle token placeholders within cached pages.
Step 1: Victim Interaction: A user (victim) interacts with a webform that contains token placeholders for default values. These placeholders are designed to dynamically populate content based on the user's session.
Step 2: Page Caching: The vulnerable Webform module caches the page containing the token placeholders. Due to the vulnerability, the cached version is not personalized for the user.
Step 3: Attacker Access: An attacker accesses the cached page. Because the page is cached and not personalized, the attacker receives the page with the token placeholders, which may contain session-specific information.
Step 4: Information Disclosure: The attacker potentially gains access to the session data of the victim or other users, depending on the nature of the token placeholders and the information they contain. This could include session IDs, user roles, or other sensitive data.
The vulnerability stems from the Webform module's improper handling of token placeholders within cached pages. When a page containing token placeholders for default values is cached, the placeholders are not properly evaluated or personalized for each user. This results in the cached page containing the token placeholders, which, when accessed by another user, could reveal session-specific information intended only for the original user. The root cause is a lack of proper cache invalidation or personalization of token replacement during the caching process, leading to a cache poisoning vulnerability. The module fails to distinguish between different user sessions when rendering and caching pages with dynamic content, specifically those utilizing token placeholders for default values. This allows an attacker to potentially retrieve sensitive data, such as session IDs or other user-specific information, that is meant to be unique to each user's session.
While no specific APTs are directly linked to this CVE, the nature of the vulnerability (session data disclosure) makes it attractive to various threat actors. This type of vulnerability could be used by attackers to gain initial access, escalate privileges, or conduct reconnaissance. The potential for credential theft makes it a valuable asset for any attacker. CISA KEV status: Not Listed
Monitor web server logs for unusual access patterns to webform pages, especially those with token placeholders in default values.
Analyze HTTP response headers for caching-related information (e.g., Cache-Control, Expires). Look for unexpected caching of pages that should be dynamic.
Implement intrusion detection system (IDS) rules to identify suspicious requests targeting webform pages with specific parameters or patterns related to token placeholders.
Review Drupal access logs for suspicious activity, such as multiple requests from the same IP address accessing webform pages.
Examine the Drupal database for evidence of unauthorized access or data modification related to user sessions.
Upgrade the Webform module to version 5.x-2.8 or 6.x-2.8 or later.
Implement proper cache invalidation strategies for pages containing dynamic content, ensuring that user-specific information is not cached.
Review and audit all webforms for the use of token placeholders in default values. Minimize their use where possible.
Configure Drupal's caching settings to prevent caching of pages that contain sensitive information or dynamic content.
Regularly update Drupal core and all installed modules to address known vulnerabilities.
Implement a web application firewall (WAF) to filter malicious requests and protect against common web attacks.