CVE-2007-4944 in Web Browser
Summary
by MITRE
The canvas.createPattern function in Opera 9.x before 9.22 for Linux, FreeBSD, and Solaris does not clear memory before using it to process a new pattern, which allows remote attackers to obtain sensitive information (memory contents) via JavaScript.
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Analysis
by VulDB Data Team • 07/27/2019
The vulnerability identified as CVE-2007-4944 represents a critical information disclosure flaw within the Opera web browser's canvas implementation. This issue specifically affects Opera 9.x versions prior to 9.22 across multiple operating systems including Linux, FreeBSD, and Solaris. The vulnerability stems from improper memory management within the canvas.createPattern function, which is a core component of the HTML5 canvas API used for rendering graphics on web pages. The flaw manifests when the browser fails to properly clear memory segments before reusing them for processing new graphical patterns, creating a scenario where residual data from previous operations can persist in memory and potentially be accessed by malicious JavaScript code.
The technical nature of this vulnerability aligns with CWE-225, which describes improper handling of memory in web browser implementations, and more specifically with CWE-200, concerning the exposure of sensitive information through improper memory clearing. When attackers exploit this vulnerability, they can leverage JavaScript code to access memory contents that should not be exposed to web applications. This occurs because the canvas.createPattern function does not properly sanitize memory before processing new pattern data, allowing for information leakage that could include sensitive data from other applications, user sessions, or system resources that were previously stored in the same memory regions. The exploitation typically involves crafting malicious JavaScript code that repeatedly calls the createPattern function while monitoring memory contents for sensitive information that may have been left in memory from previous operations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential pathways for more sophisticated attacks that could lead to session hijacking, credential theft, or further exploitation of the affected system. Attackers could potentially gather sensitive information such as session tokens, user credentials, or other confidential data that was previously stored in memory locations that are now being reused. This vulnerability particularly affects users of older Opera versions who may be running on enterprise systems or environments where upgrading browsers is not immediately possible. The attack vector is entirely remote and requires no special privileges, making it particularly dangerous as it can be exploited through standard web browsing activities without user interaction beyond visiting a malicious website.
Mitigation strategies for this vulnerability require immediate browser updates to Opera 9.22 or later versions where the memory clearing issue has been addressed. System administrators should prioritize patching affected systems and implementing browser security policies that restrict access to potentially dangerous JavaScript functions. Organizations should also consider implementing network monitoring to detect unusual memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper memory management in browser implementations and highlights the need for regular security updates. From an ATT&CK perspective, this vulnerability maps to technique T1059.007 for JavaScript execution and T1005 for data from local system, as attackers can leverage this flaw to extract sensitive information from the target system through browser-based attacks. Organizations should also implement web application firewalls and content security policies to limit the potential impact of such vulnerabilities in environments where immediate patching is not feasible.