CVE-2012-4144 in Web Browser
Summary
by MITRE
Opera before 12.01 on Windows and UNIX, and before 11.66 and 12.x before 12.01 on Mac OS X, does not properly escape characters in DOM elements, which makes it easier for remote attackers to bypass cross-site scripting (XSS) protection mechanisms via a crafted HTML document.
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Analysis
by VulDB Data Team • 03/27/2021
This vulnerability resides in the Opera web browser's handling of DOM element character escaping mechanisms, specifically affecting versions prior to 12.01 on Windows and UNIX platforms and versions before 11.66 and 12.x before 12.01 on Mac OS X. The flaw represents a classic cross-site scripting security weakness that undermines the browser's built-in XSS protection measures. The vulnerability stems from Opera's insufficient sanitization of character sequences within DOM elements, allowing malicious actors to craft HTML documents that can bypass the browser's security controls designed to prevent XSS attacks.
The technical implementation of this vulnerability involves Opera's failure to properly escape special characters when processing DOM elements, creating opportunities for attackers to inject malicious scripts that would otherwise be neutralized by the browser's XSS filtering mechanisms. This character escaping deficiency enables attackers to construct HTML documents containing malicious payloads that can execute in the context of a victim's browser session. The vulnerability specifically affects how Opera processes and renders HTML content, particularly when encountering certain character sequences that should be properly escaped to prevent script execution.
Operationally, this vulnerability poses significant risks to users who browse the internet with affected Opera versions, as it allows remote attackers to execute arbitrary code in the context of the victim's browser session. The impact extends beyond simple script injection to potentially enable full session hijacking, data theft, and privilege escalation attacks. Attackers can craft malicious web pages that appear legitimate but contain hidden scripts that exploit this character escaping flaw, making it particularly dangerous for users who visit untrusted websites or click on malicious links. The vulnerability affects both desktop operating systems and mobile platforms, though the specific version constraints indicate targeted exposure windows.
The security implications align with CWE-79 which defines Cross-Site Scripting vulnerabilities, and the attack vector maps to ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should immediately upgrade to Opera versions 12.01 or later on all supported platforms to remediate this vulnerability. Additional mitigations include implementing strict content security policies, enabling browser security features such as XSS protection filters, and educating users about the risks of visiting untrusted websites. Network-level protections such as web application firewalls and intrusion prevention systems can provide additional layers of defense, though the most effective solution remains the immediate deployment of patched browser versions to eliminate the character escaping vulnerability that enables successful XSS attacks against affected Opera installations.