CVE-2021-33697 in BusinessObjects Business Intelligence Platform
Summary
by MITRE • 09/16/2021
Under certain conditions, SAP BusinessObjects Business Intelligence Platform (SAPUI5), versions - 420, 430, can allow an unauthenticated attacker to redirect users to a malicious site due to Reverse Tabnabbing vulnerabilities.
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Analysis
by VulDB Data Team • 09/19/2021
The vulnerability identified as CVE-2021-33697 affects SAP BusinessObjects Business Intelligence Platform with SAPUI5 components in versions 420 and 430. This represents a critical security flaw that exploits the reverse tabnabbing attack vector, which is classified under CWE-1022. The vulnerability enables unauthenticated attackers to manipulate the target attribute of HTML links, creating a dangerous redirection scenario that can compromise user sessions and data integrity. Reverse tabnabbing occurs when an attacker controls a webpage that opens a link in a new tab or window, and then uses JavaScript to access the original tab through the window.opener property, potentially redirecting users to malicious sites without their knowledge.
The technical implementation of this vulnerability stems from insufficient validation of the target attribute in HTML anchor tags within the SAPUI5 framework. When users navigate to web pages containing malicious links, the platform fails to properly sanitize or validate the target parameter, allowing attackers to inject malicious URLs that redirect users upon tab switching. This flaw specifically impacts the user authentication and session management mechanisms within the SAP BusinessObjects environment, creating an attack surface that can be exploited through social engineering campaigns or compromised web pages. The vulnerability is particularly concerning because it operates at the browser level and can bypass traditional security controls that focus on server-side validation.
The operational impact of CVE-2021-33697 extends beyond simple phishing attacks, as it can facilitate more sophisticated attacks including credential theft, session hijacking, and data exfiltration. Attackers can leverage this vulnerability to redirect users to malicious sites that appear legitimate, potentially harvesting login credentials or sensitive business intelligence information. The attack vector aligns with techniques documented in the MITRE ATT&CK framework under the T1566 category for Phishing and T1531 for Account Access Removal. Organizations using affected SAP versions face significant risk of unauthorized access to their business intelligence platforms, potentially compromising sensitive data and business operations. The vulnerability affects the trust model of the platform, as users may unknowingly navigate to malicious sites while working within what appears to be a legitimate SAP environment.
Mitigation strategies for CVE-2021-33697 should include immediate application of SAP security notes and patches, specifically addressing the reverse tabnabbing vulnerability in SAPUI5 components. Organizations should implement proper HTML sanitization of anchor tags and target attributes, particularly when handling user-generated content or external links within the platform. Network-level controls such as web application firewalls and content filtering solutions can provide additional protection by monitoring and blocking suspicious redirection patterns. Security teams should also conduct comprehensive vulnerability assessments to identify any custom applications or integrations that may be vulnerable to similar reverse tabnabbing attacks. The implementation of proper security headers including the rel="noopener" attribute on external links can prevent the window.opener access that enables this attack, while regular security awareness training for users can help identify potential social engineering attempts that may exploit this vulnerability.