Source: cve@mitre.org
Open redirect vulnerability in the FAQ Ask module 5.x and 6.x before 6.x-2.0, a module for Drupal, allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.
Drupal's FAQ Ask module versions 5.x and 6.x prior to 6.x-2.0 are vulnerable to an open redirect attack. This allows attackers to craft malicious links that redirect users to arbitrary websites, potentially leading to phishing and credential theft, compromising user trust and potentially leading to further system compromise.
Step 1: Crafting the Malicious URL: The attacker identifies a vulnerable Drupal website using the FAQ Ask module. They construct a URL that exploits the open redirect vulnerability. This URL typically includes a parameter that specifies the redirection target (e.g., ?redirect=http://malicious.com).
Step 2: User Interaction: The attacker distributes the malicious URL through various channels (e.g., email, social media, or other websites). A user clicks on the malicious link.
Step 3: Server-Side Processing: The Drupal website, using the vulnerable FAQ Ask module, receives the request. It processes the URL, likely extracting the redirection target from the parameter.
Step 4: Unvalidated Redirection: The module, due to the lack of input validation, uses the attacker-supplied URL to redirect the user. This is often done using a header() function in PHP or a similar redirection mechanism.
Step 5: Redirection to Malicious Site: The user's browser is redirected to the attacker-controlled website (e.g., a phishing site). The attacker can then attempt to steal credentials, install malware, or perform other malicious activities.
The vulnerability stems from insufficient input validation and sanitization of user-supplied data used in the redirection process. Specifically, the module likely fails to properly validate the target URL provided by the attacker. This allows an attacker to inject a malicious URL, which is then used in a header() or similar function to redirect the user. The lack of proper validation allows the attacker to control the destination URL, enabling them to redirect users to phishing sites or other malicious destinations. The root cause is a missing or inadequate check on the user-provided URL, allowing for arbitrary redirection. This is a classic example of a security misconfiguration vulnerability.
This type of vulnerability is often exploited by a wide range of actors, from opportunistic attackers to more sophisticated groups. It's a common initial access vector. There is no specific APT attribution for this CVE, but it is a type of vulnerability that is often used by various threat actors. This CVE is not listed in the CISA KEV catalog, but open redirect vulnerabilities are a common attack vector and thus are indirectly addressed by the KEV program's focus on remediating known exploited vulnerabilities.
Analyze web server logs for suspicious HTTP requests containing parameters that suggest redirection attempts (e.g., redirect=, url=, return=).
Monitor network traffic for unusual HTTP redirects to external domains, especially those with suspicious domain names or URLs.
Implement a Web Application Firewall (WAF) with rules to detect and block open redirect attempts.
Use a Security Information and Event Management (SIEM) system to correlate logs and identify potential exploitation attempts.
Examine the source code of the FAQ Ask module (if available) for the presence of redirection functions and the lack of input validation.
Upgrade the FAQ Ask module to version 6.x-2.0 or later.
Implement robust input validation to sanitize and validate all user-supplied URLs before redirection. This includes checking the URL's scheme (e.g., http or https) and ensuring it points to a trusted domain.
Use a whitelist approach for allowed redirect destinations, rather than a blacklist.
Implement output encoding to prevent cross-site scripting (XSS) vulnerabilities that could be used in conjunction with the open redirect.
Regularly scan the Drupal installation for outdated modules and vulnerabilities.
Review and harden the web server configuration to prevent unauthorized access and exploitation.