CVE-2014-7940 in Communications Messaging Server
Summary
by MITRE
The collator implementation in i18n/ucol.cpp in International Components for Unicode (ICU) 52 through SVN revision 293126, as used in Google Chrome before 40.0.2214.91, does not initialize memory for a data structure, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted character sequence.
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Analysis
by VulDB Data Team • 06/23/2022
The vulnerability identified as CVE-2014-7940 resides within the International Components for Unicode (ICU) library, specifically in the collator implementation located at i18n/ucol.cpp. This flaw affects ICU versions 52 through SVN revision 293126 and was notably present in Google Chrome versions prior to 40.0.2214.91. The issue manifests when the collator processes character sequences that trigger memory initialization failures in critical data structures, creating a potential vector for remote exploitation. The vulnerability represents a classic case of uninitialized memory access that can be leveraged by malicious actors to disrupt system operations or potentially execute arbitrary code.
The technical root cause of this vulnerability stems from improper memory initialization within the ICU collator's data structure handling mechanisms. When processing crafted character sequences, the collator fails to properly initialize certain memory regions before utilizing them, leading to undefined behavior. This uninitialized memory access creates opportunities for attackers to craft specific input patterns that can trigger memory corruption or access violations. The flaw operates at the intersection of internationalization libraries and web browser security, where Unicode collation algorithms must handle complex character processing while maintaining memory safety. According to CWE classification, this vulnerability maps to CWE-457: Use of Uninitialized Variable, which describes the use of uninitialized memory locations in program execution, potentially leading to unpredictable behavior and security consequences.
The operational impact of CVE-2014-7940 extends beyond simple denial of service scenarios, as the uninitialized memory access could potentially enable more sophisticated attacks. Remote attackers can exploit this vulnerability by crafting malicious character sequences that, when processed by the ICU collator, cause the browser to crash or behave unpredictably. In some cases, the memory corruption could be leveraged to execute arbitrary code, particularly when the vulnerable system processes user-supplied content through the affected ICU components. The vulnerability's presence in Google Chrome made it particularly dangerous as it affected a widely used browser with extensive web interaction capabilities. The attack surface is broad since collation operations are fundamental to text processing in internationalized applications, making this flaw potentially exploitable across numerous web applications and services that rely on ICU for Unicode handling.
Mitigation strategies for CVE-2014-7940 primarily focus on updating to patched versions of the ICU library and affected browser software. The most effective immediate solution involves upgrading Google Chrome to version 40.0.2214.91 or later, which includes the necessary fixes for the uninitialized memory issue. System administrators should also ensure that all applications using ICU libraries are updated to versions that address this vulnerability. Additionally, implementing input validation and sanitization measures can help reduce the risk of exploitation by filtering out potentially malicious character sequences before they reach the collator implementation. The vulnerability highlights the importance of proper memory initialization practices in security-critical code components, particularly in internationalization libraries that handle user input. Organizations should also consider implementing runtime protections such as address space layout randomization and stack canaries to make exploitation more difficult, while following ATT&CK framework recommendations for defending against memory corruption vulnerabilities.