CVE-2012-2856 in Chrome
Summary
by MITRE
The PDF functionality in Google Chrome before 21.0.1180.57 on Mac OS X and Linux, and before 21.0.1180.60 on Windows and Chrome Frame, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors that trigger out-of-bounds write operations.
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Analysis
by VulDB Data Team • 05/10/2021
The vulnerability identified as CVE-2012-2856 represents a critical security flaw in Google Chrome's PDF rendering functionality across multiple operating systems. This issue affects Chrome versions prior to 21.0.1180.57 on macOS and Linux platforms, and versions before 21.0.1180.60 on Windows systems and Chrome Frame extensions. The vulnerability stems from improper bounds checking within the PDF processing engine, which fails to validate input data before attempting to write to memory locations. This fundamental flaw creates an avenue for malicious actors to exploit the browser's PDF handling capabilities and potentially compromise system integrity.
The technical nature of this vulnerability aligns with CWE-787, which describes out-of-bounds write operations that occur when a program writes data past the end of a buffer or array. In Chrome's case, the PDF rendering component does not adequately validate the size or structure of PDF objects before processing them, leading to memory corruption scenarios. When a specially crafted PDF file is loaded, the browser's PDF engine attempts to write data beyond allocated memory boundaries, triggering either immediate system crashes or more subtle memory corruption that could be leveraged for further exploitation. This vulnerability operates at the intersection of software security and memory management, where improper input validation creates opportunities for attackers to manipulate program execution flow.
The operational impact of CVE-2012-2856 extends beyond simple denial of service conditions to potentially enable more sophisticated attacks. While the initial exploit may result in browser crashes or application instability, the underlying memory corruption could provide attackers with opportunities to execute arbitrary code on affected systems. This makes the vulnerability particularly dangerous in enterprise environments where Chrome is widely deployed, as successful exploitation could lead to complete system compromise. The cross-platform nature of the vulnerability means that organizations using Chrome across different operating systems must implement immediate mitigations to protect their infrastructure from potential attacks.
Organizations should prioritize immediate patching of affected Chrome versions to address this vulnerability. The recommended mitigation involves updating to Chrome versions 21.0.1180.57 or later on macOS and Linux, and 21.0.1180.60 or later on Windows systems. Additionally, implementing network-based protections such as web application firewalls and content filtering systems can provide additional layers of defense against malicious PDF files. Security teams should also monitor for indicators of compromise related to this vulnerability and consider implementing browser hardening measures including sandboxing and privilege separation. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for 'Command and Scripting Interpreter: JavaScript' as attackers may leverage the PDF functionality to deliver malicious JavaScript payloads. Organizations should also consider deploying endpoint detection and response solutions to identify potential exploitation attempts and maintain comprehensive incident response procedures for handling such security incidents.