CVE-2012-5109 in Chrome
Summary
by MITRE
The International Components for Unicode (ICU) functionality in Google Chrome before 22.0.1229.92 allows remote attackers to cause a denial of service (out-of-bounds read) via vectors related to a regular expression.
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Analysis
by VulDB Data Team • 04/18/2021
The vulnerability identified as CVE-2012-5109 represents a critical out-of-bounds read flaw within the International Components for Unicode (ICU) implementation used by Google Chrome browser. This issue specifically affects Chrome versions prior to 22.0.1229.92 and demonstrates how seemingly benign regular expression processing can become a vector for significant security impacts. The vulnerability resides in the ICU library's handling of regular expression patterns, where improper boundary checking allows malicious inputs to trigger memory access violations that can lead to application instability and potential system compromise.
The technical exploitation of this vulnerability occurs when Chrome processes regular expressions containing specially crafted patterns that cause the ICU library to access memory locations beyond the allocated buffer boundaries. This out-of-bounds read condition manifests during the parsing and execution of regular expressions, particularly those involving Unicode character sequences or complex pattern matching operations. The flaw essentially allows attackers to manipulate the memory access patterns within the ICU component, potentially leading to information disclosure or system instability. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions in software implementations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially enable more sophisticated attacks when combined with other exploitation techniques. Remote attackers can leverage this flaw to cause Chrome to crash or behave unpredictably, effectively creating a denial of service condition that impacts user experience and potentially providing a foothold for further attacks. The vulnerability's presence in the ICU library means that any application utilizing this component for text processing and regular expression matching could be similarly affected, though the primary concern focuses on Chrome's browser environment where such attacks could be executed through malicious web content.
Mitigation strategies for CVE-2012-5109 primarily involve updating to Chrome version 22.0.1229.92 or later, which contains the necessary patches to address the out-of-bounds read condition in the ICU implementation. Organizations should prioritize patch management to ensure all affected systems receive the security updates promptly. Additionally, implementing network-level controls such as web application firewalls and content filtering systems can provide additional protection layers. The ATT&CK framework categorizes this vulnerability under the 'Exploitation for Defense Evasion' tactic, as attackers could potentially use such flaws to bypass security controls or maintain persistent access through stable exploitation methods. Security teams should also consider monitoring for unusual browser behavior or crashes that might indicate exploitation attempts, particularly when users encounter complex web content or regular expression processing scenarios.