CVE-2021-33331 in Liferay
Summary
by MITRE • 08/04/2021
Open redirect vulnerability in the Notifications module in Liferay Portal 7.0.0 through 7.3.1, and Liferay DXP 7.0 before fix pack 94, 7.1 before fix pack 19 and 7.2 before fix pack 8, allows remote attackers to redirect users to arbitrary external URLs via the 'redirect' parameter.
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Analysis
by VulDB Data Team • 05/14/2025
The CVE-2021-33331 vulnerability represents a critical open redirect flaw within the Notifications module of Liferay Portal and Liferay DXP platforms. This vulnerability affects multiple versions including Liferay Portal 7.0.0 through 7.3.1 and specific DXP versions before their respective fix packs. The flaw resides in how the system processes the 'redirect' parameter, creating an opportunity for attackers to manipulate user navigation flows. Such vulnerabilities typically arise from insufficient input validation and sanitization of user-provided parameters that are subsequently used in redirect operations.
The technical implementation of this vulnerability stems from the lack of proper validation of redirect URLs within the notifications framework. When users interact with notification links or forms that utilize the redirect parameter, the application fails to adequately verify the destination URLs against a whitelist or validate their legitimacy. This allows malicious actors to craft specially crafted URLs that redirect users to phishing sites, malicious domains, or other attacker-controlled resources. The vulnerability operates at the application layer and can be exploited through web-based attacks without requiring authentication or elevated privileges. According to CWE standards, this maps directly to CWE-601: URL Redirection to Untrusted Site ('Open Redirect'), which is classified as a high-severity weakness in the CWE top 25 list.
The operational impact of this vulnerability extends beyond simple user inconvenience to potentially severe security implications. Attackers can leverage this flaw to conduct phishing campaigns where users are redirected to convincing fake login pages designed to capture credentials. The vulnerability can also be used to spread malware through malicious redirects or to perform social engineering attacks by directing users to attacker-controlled content. Users who trust the legitimate Liferay portal may unknowingly navigate to malicious sites, creating a significant risk for organizations that rely on these platforms for business-critical operations. The open redirect vulnerability can be particularly dangerous in enterprise environments where users frequently interact with portal notifications and may not scrutinize URLs carefully. From an ATT&CK framework perspective, this vulnerability aligns with T1566.001: Phishing and T1071.004: Application Layer Protocol: DNS, as it enables initial access through deceptive redirect mechanisms.
Organizations should implement immediate mitigations including input validation for all redirect parameters, implementing strict URL validation mechanisms, and establishing comprehensive redirect whitelisting policies. The most effective long-term solution involves applying the vendor-provided patches and fix packs for the affected versions, particularly the specific fix packs mentioned in the vulnerability description. Security teams should also consider implementing web application firewalls with redirect validation capabilities and conducting regular security testing to identify similar vulnerabilities. Additional protective measures include user education about suspicious redirects, monitoring of redirect patterns in web logs, and implementing security headers such as Content Security Policy to limit redirect behaviors. Organizations should also review their notification systems and ensure that all redirect parameters are properly validated against trusted domains only, following the principle of least privilege in URL redirection mechanisms.