CVE-2011-1824 in Web Browser
Summary
by MITRE
The VEGAOpBitmap::AddLine function in Opera before 10.61 does not properly initialize memory during processing of the SIZE attribute of a SELECT element, which allows remote attackers to trigger an invalid memory write operation, and consequently cause a denial of service (application crash) or possibly execute arbitrary code, via a large integer attribute value.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/07/2021
The vulnerability identified as CVE-2011-1824 resides within the VEGAOpBitmap::AddLine function of the Opera web browser version 10.60 and earlier. This flaw represents a classic memory corruption issue that arises from improper memory initialization during the processing of HTML SELECT elements. The vulnerability specifically targets the SIZE attribute of SELECT elements, which controls the number of visible options in a dropdown list. When an attacker crafts a malicious HTML document containing a SELECT element with an unusually large integer value in its SIZE attribute, the browser's rendering engine fails to properly validate or initialize memory structures before processing this input.
The technical implementation of this vulnerability stems from a buffer overflow condition that occurs when the browser attempts to allocate memory for rendering the SELECT element's visual representation. The VEGAOpBitmap::AddLine function, which handles bitmap operations for graphical rendering, does not adequately validate the SIZE attribute value against reasonable bounds before proceeding with memory allocation. This lack of input validation creates an opportunity for attackers to manipulate the memory allocation process by specifying an excessively large integer value that exceeds the intended processing limits. The improper memory initialization allows for an invalid memory write operation to occur, where the application attempts to write data beyond the allocated memory boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution. When an attacker successfully triggers this vulnerability through a maliciously crafted webpage, the browser may crash due to the invalid memory write, resulting in a denial of service attack that prevents legitimate users from accessing the affected system. However, the more severe implications arise when the memory corruption is carefully crafted to overwrite critical program structures or function pointers, potentially allowing attackers to execute arbitrary code with the privileges of the compromised browser process. This vulnerability demonstrates the dangerous intersection of memory management flaws and web browser security, where a single malformed attribute can compromise entire systems.
Security professionals should recognize this vulnerability as a variant of CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write errors. The attack vector aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for remote code execution. Organizations should prioritize immediate patching of affected Opera versions to address this memory corruption vulnerability, as the combination of remote exploitability and potential privilege escalation makes it a critical security concern. Additionally, implementing web application firewalls and content filtering solutions can provide additional layers of protection against exploitation attempts, while regular security assessments should include testing for similar memory handling vulnerabilities in other browser components and web applications.