CVE-2013-2909 in Chrome
Summary
by MITRE
Use-after-free vulnerability in Blink, as used in Google Chrome before 30.0.1599.66, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to inline-block rendering for bidirectional Unicode text in an element isolated from its siblings.
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Analysis
by VulDB Data Team • 02/03/2019
The vulnerability identified as CVE-2013-2909 represents a critical use-after-free flaw within the Blink rendering engine that powers Google Chrome browser. This vulnerability specifically affects versions prior to 30.0.1599.66 and demonstrates how complex text rendering mechanisms can be exploited to compromise system stability and potentially enable more severe attacks. The issue manifests during the processing of inline-block elements that contain bidirectional Unicode text, where the browser's handling of text isolation creates conditions that allow memory corruption.
The technical root cause of this vulnerability lies in improper memory management during the rendering process of bidirectional Unicode text within isolated inline-block elements. When Chrome processes such text elements, the rendering engine fails to properly manage memory references after objects have been freed, creating a use-after-free condition. This occurs specifically when the browser encounters text that requires bidirectional rendering, where characters may need to be displayed in different directions based on their linguistic context. The isolation mechanism that separates these elements from their siblings creates a scenario where memory deallocation happens prematurely, but subsequent operations attempt to access the freed memory locations.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the use-after-free condition can potentially be exploited to execute arbitrary code on affected systems. Attackers can craft malicious web pages containing carefully constructed bidirectional Unicode text within inline-block elements to trigger the vulnerable code path. The vulnerability's remote exploitability means that simply visiting a compromised website could result in system compromise, making it particularly dangerous in web-based attack scenarios. This type of vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in memory management, and represents a classic example of how improper object lifecycle management can lead to security breaches.
The exploitation of this vulnerability typically involves creating web content that forces the browser to process bidirectional Unicode text within isolated inline-block elements, triggering the memory corruption. The attack vector leverages the browser's text rendering capabilities to manipulate memory states, potentially leading to privilege escalation or complete system compromise depending on the execution environment. Security researchers have noted that the vulnerability's impact can vary based on the target system's memory layout and the specific browser configuration, but the fundamental risk remains consistent across affected implementations. Organizations should consider implementing browser hardening measures and ensuring timely patch deployment to mitigate this risk.
Mitigation strategies for CVE-2013-2909 primarily focus on immediate patching of affected Chrome versions to the secure release 30.0.1599.66 or later. Additionally, browser security configurations can be enhanced through the implementation of content security policies that restrict potentially dangerous rendering operations. The vulnerability's classification under ATT&CK technique T1059.008, which covers scripting languages, underscores the importance of browser sandboxing and memory protection mechanisms. Network administrators should also consider implementing web filtering solutions that can detect and block malicious content targeting this specific vulnerability. Regular security assessments and vulnerability scanning should include verification of Chrome browser versions to ensure compliance with security baselines. The incident highlights the critical importance of maintaining up-to-date browser software and demonstrates how seemingly benign text rendering features can become attack surfaces when not properly secured against memory corruption vulnerabilities.