CVE-2021-21189 in Edge
Summary
by MITRE • 03/10/2021
Insufficient policy enforcement in payments in Google Chrome prior to 89.0.4389.72 allowed a remote attacker to bypass navigation restrictions via a crafted HTML page.
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Analysis
by VulDB Data Team • 03/30/2021
The vulnerability identified as CVE-2021-21189 represents a critical security flaw in Google Chrome's payment processing system that existed prior to version 89.0.4389.72. This issue stems from inadequate policy enforcement mechanisms that govern how Chrome handles payment requests and navigation restrictions within web applications. The flaw specifically affects the browser's ability to properly validate and enforce security policies when processing payment transactions, creating a potential pathway for malicious actors to circumvent intended security controls.
The technical implementation of this vulnerability lies in Chrome's insufficient validation of navigation restrictions during payment processing workflows. When a web page attempts to initiate a payment request, Chrome should enforce strict policy controls that prevent unauthorized navigation or redirection attempts. However, the flaw allows attackers to craft specially designed HTML pages that can bypass these navigation restrictions, effectively undermining the security boundaries that should protect users during financial transactions. This occurs because the browser fails to properly verify the legitimacy of navigation attempts that occur during payment processing, enabling malicious actors to redirect users to unintended destinations.
The operational impact of this vulnerability extends beyond simple navigation bypassing, as it directly compromises the security of payment processing workflows that users trust to be secure. Attackers could potentially exploit this flaw to redirect users to phishing sites during payment transactions, capture sensitive payment information, or manipulate the payment flow to redirect funds to unauthorized recipients. The vulnerability particularly affects users who engage in online commerce, as it undermines the integrity of the payment confirmation and processing steps that are critical for secure transactions. Security researchers have noted that this issue could be particularly dangerous in environments where users perform financial transactions through web browsers, as it creates opportunities for sophisticated social engineering attacks that leverage the browser's payment processing capabilities.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-693, which addresses Protection Mechanism Failure, specifically in the context of policy enforcement mechanisms. The flaw also intersects with ATT&CK technique T1566, which covers Phishing, as attackers could leverage this vulnerability to create more convincing phishing campaigns that appear legitimate during payment processing. The vulnerability demonstrates how insufficient input validation and policy enforcement can create security gaps that adversaries can exploit to bypass intended protections. Organizations and users should be particularly concerned about this vulnerability because it affects a core browser functionality that millions of users interact with daily during online payment processing.
Mitigation strategies for CVE-2021-21189 primarily focus on updating to Chrome version 89.0.4389.72 or later, which includes the necessary policy enforcement improvements. Additionally, security teams should implement network-level monitoring to detect suspicious navigation patterns during payment processing, particularly when users are engaged in financial transactions. Browser security configurations should be reviewed to ensure that appropriate restrictions are in place for payment processing workflows, and users should be educated about the importance of verifying payment destination URLs before confirming transactions. Organizations that deploy Chrome in enterprise environments should consider implementing additional security measures such as content filtering and web application firewalls to provide defense-in-depth against exploitation attempts targeting this vulnerability.