CVE-2011-2791 in Chrome
Summary
by MITRE
The International Components for Unicode (ICU) functionality in Google Chrome before 13.0.782.107 allows remote attackers to cause a denial of service or possibly have unspecified other impact via unknown vectors that trigger an out-of-bounds write.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/16/2021
The vulnerability identified as CVE-2011-2791 affects the International Components for Unicode (ICU) implementation within Google Chrome browser versions prior to 13.0.782.107. This issue represents a critical security flaw that resides in the browser's handling of Unicode text processing capabilities, which are essential for supporting international character sets and multilingual content on web pages. The ICU library serves as a foundational component for text processing, string manipulation, and internationalization features across various software applications, making its security paramount to overall system integrity. When Chrome incorporates ICU functionality for rendering and processing Unicode text, it becomes susceptible to memory corruption vulnerabilities that can be exploited through carefully crafted web content.
The technical flaw manifests as an out-of-bounds write condition that occurs when the browser processes specific Unicode sequences or text patterns through its ICU implementation. This type of vulnerability typically arises when application code fails to properly validate input boundaries or perform adequate bounds checking before writing data to memory locations. The out-of-bounds write can potentially overwrite adjacent memory regions, leading to unpredictable behavior including application crashes, memory corruption, or in more severe cases, arbitrary code execution. The vulnerability's classification as an unspecified other impact suggests that while the primary effect is denial of service, there exists potential for more serious consequences including information disclosure or privilege escalation depending on the specific exploitation scenario. The complexity of Unicode processing within ICU libraries increases the attack surface significantly, as these components must handle diverse character encodings, collation rules, and text transformation operations across multiple languages and scripts.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable sophisticated attack vectors that could compromise user systems. Remote attackers can leverage this weakness by hosting malicious web content that triggers the vulnerable ICU processing path when users browse to affected sites. The denial of service aspect can be used to repeatedly crash the browser, rendering it unusable for legitimate web browsing activities and potentially causing users to lose unsaved work or access to important web applications. When combined with other exploitation techniques, the out-of-bounds write vulnerability could allow attackers to execute arbitrary code with the privileges of the browser process, potentially leading to complete system compromise. This risk is particularly concerning given Chrome's widespread adoption and the fact that users often interact with untrusted web content regularly, making the attack surface substantial and the potential impact significant across enterprise and individual user environments.
Mitigation strategies for CVE-2011-2791 primarily focus on immediate browser updates and system hardening measures. Organizations should prioritize patching affected Chrome installations to version 13.0.782.107 or later, which contains the necessary fixes for the ICU memory corruption vulnerability. Additionally, implementing network-level protections such as web application firewalls and content filtering systems can help reduce exposure to malicious web content that might trigger this vulnerability. Browser hardening techniques including sandboxing mechanisms, address space layout randomization, and strict memory access controls should be enabled to limit the potential impact if exploitation occurs. Security monitoring and incident response procedures should be enhanced to detect unusual browser behavior or crash patterns that might indicate exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-787 Out-of-bounds Write and follows patterns commonly associated with the ATT&CK technique T1059 Command and Scripting Interpreter, as exploitation may involve crafting malicious scripts or content that triggers the vulnerable code path. Organizations should also consider implementing user education programs to raise awareness about avoiding untrusted web content and maintaining up-to-date software versions to minimize exposure to similar vulnerabilities in the future.