CVE-2011-0450 in Web Browser
Summary
by MITRE
The downloads manager in Opera before 11.01 on Windows does not properly determine the pathname of the filesystem-viewing application, which allows user-assisted remote attackers to execute arbitrary code via a crafted web site that hosts an executable file.
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Analysis
by VulDB Data Team • 03/18/2021
The vulnerability identified as CVE-2011-0450 represents a critical security flaw in Opera web browser versions prior to 11.01 on Windows operating systems. This issue resides within the browser's downloads manager component and stems from improper handling of filesystem pathnames when determining which application should open downloaded files. The flaw creates a path traversal condition that can be exploited by remote attackers who craft malicious websites to manipulate how the browser processes executable downloads. The vulnerability specifically affects Windows environments where Opera's download handling mechanism fails to properly validate or sanitize the pathname information associated with filesystem viewing applications.
The technical nature of this vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The flaw occurs when Opera's downloads manager fails to properly resolve or validate the absolute or relative pathnames of applications that should handle downloaded files. Attackers can exploit this by creating a malicious website that hosts an executable file and manipulates the download process to execute arbitrary code on the victim's system. The vulnerability requires user interaction through visiting a malicious website and downloading an executable file, making it a user-assisted remote code execution vulnerability that leverages the browser's trust in local filesystem operations.
Operationally, this vulnerability poses significant risk to users who browse the internet without proper security measures or browser updates. The attack vector requires a user to visit a compromised website and download an executable file, which then gets executed through the browser's downloads manager. This creates a scenario where attackers can bypass traditional security controls by leveraging the browser's legitimate file handling mechanisms. The impact extends beyond simple code execution to potentially allow full system compromise, as the executed code can perform any action available to the user account running the browser. The vulnerability affects all Windows users of Opera versions before 11.01, making it a widespread concern for organizations relying on this browser for web browsing activities.
Mitigation strategies for this vulnerability include immediate installation of Opera version 11.01 or later, which contains the necessary patches to properly validate filesystem pathnames in the downloads manager. Organizations should also implement browser hardening measures such as disabling automatic downloads, implementing strict download permissions, and using security software that can detect and block malicious file downloads. The vulnerability demonstrates the importance of proper input validation and path resolution in browser security implementations, aligning with ATT&CK technique T1059 for command and scripting interpreter and T1203 for exploitation for client execution. Additionally, users should maintain awareness of suspicious download prompts and verify the legitimacy of downloaded files before execution, as this vulnerability specifically targets the trust relationship between the browser and local filesystem operations.