CVE-2012-3556 in Web Browser
Summary
by MITRE
Opera before 11.65 does not properly restrict the opening of a pop-up window in response to the first click of a double-click action, which makes it easier for user-assisted remote attackers to conduct cross-site scripting (XSS) attacks or execute arbitrary code via a crafted web site.
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Analysis
by VulDB Data Team • 03/25/2021
The vulnerability identified as CVE-2012-3556 affects Opera web browsers version 11.64 and earlier, representing a critical security flaw in the browser's handling of pop-up window restrictions during user interaction sequences. This issue stems from the browser's improper validation of user actions, specifically when processing double-click events that trigger pop-up window creation. The vulnerability creates a window of opportunity for malicious actors to exploit the browser's inconsistent behavior during rapid user interactions, potentially allowing attackers to bypass security mechanisms designed to prevent unauthorized pop-up windows from opening.
The technical flaw manifests in Opera's event handling system where the browser fails to properly distinguish between legitimate user interactions and maliciously crafted sequences designed to exploit the timing and sequence of click events. When a user performs a double-click action, the browser's pop-up blocker mechanism becomes inconsistent in its evaluation of whether the subsequent window opening should be permitted. This inconsistency occurs because the browser does not adequately validate that the pop-up window opening originates from a legitimate context rather than a malicious script attempting to exploit the timing window between the first and second click events. The vulnerability is particularly dangerous because it operates at the user interaction level, making it difficult to detect through traditional network-based security measures.
The operational impact of this vulnerability extends beyond simple cross-site scripting attacks to potentially enable arbitrary code execution on affected systems. Attackers can craft malicious websites that exploit the pop-up window handling behavior to execute malicious code within the browser context, potentially leading to complete system compromise. The user-assisted nature of the attack means that victims must actively interact with the malicious website, typically through a double-click action, but this requirement does not significantly reduce the risk since users often engage with web content without considering the underlying security implications. The vulnerability aligns with CWE-602, which addresses client-side attacks where the client application becomes the attack vector, and follows patterns commonly associated with the ATT&CK technique T1203, which involves exploitation of web browsers through user interaction.
Mitigation strategies for this vulnerability require immediate browser updates to version 11.65 or later, where Opera has implemented proper restrictions on pop-up window opening during double-click sequences. Security administrators should also consider implementing additional browser security measures such as enhanced pop-up blockers, content security policies, and user education regarding suspicious website interactions. Organizations should conduct thorough security assessments to ensure all Opera installations are updated and monitor for any attempts to exploit this vulnerability through web-based attacks. The fix implemented by Opera addresses the core issue by modifying the browser's event handling logic to properly validate pop-up window creation requests regardless of the click sequence, thereby eliminating the timing-based exploitation window that previously enabled these attacks.