CVE-2014-8147 in Watch
Summary
by MITRE
The resolveImplicitLevels function in common/ubidi.c in the Unicode Bidirectional Algorithm implementation in ICU4C in International Components for Unicode (ICU) before 55.1 uses an integer data type that is inconsistent with a header file, which allows remote attackers to cause a denial of service (incorrect malloc followed by invalid free) or possibly execute arbitrary code via crafted text.
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Analysis
by VulDB Data Team • 12/24/2024
The vulnerability identified as CVE-2014-8147 resides within the International Components for Unicode (ICU) library, specifically in the common/ubidi.c file that implements the Unicode Bidirectional Algorithm. This flaw affects ICU4C versions prior to 55.1 and represents a critical security issue that demonstrates poor type handling in low-level memory management functions. The vulnerability stems from a type inconsistency between the implementation and header file definitions, creating a scenario where integer data types do not align properly during memory allocation operations.
The technical flaw manifests in the resolveImplicitLevels function where an integer data type mismatch causes incorrect memory allocation calculations. When processing crafted text input, the function calculates memory requirements using an inconsistent integer type that leads to either insufficient memory allocation or incorrect sizing parameters. This misalignment results in memory allocation failures that subsequently trigger invalid free operations when the system attempts to release memory that was either not properly allocated or was allocated with incorrect parameters. The inconsistency creates a path where attackers can manipulate input text to force the system into memory management states that can lead to system instability or potential code execution.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution. Attackers can craft specific text inputs that exploit the integer type mismatch to manipulate heap memory operations, creating conditions where invalid memory access patterns may occur. This vulnerability affects systems that rely on ICU4C for text processing, particularly those handling internationalized content or user input that passes through the bidirectional algorithm implementation. The attack surface includes web applications, text processing systems, and any software that utilizes ICU4C for Unicode text handling, making it a significant concern for organizations maintaining applications that process user-generated content.
The vulnerability aligns with CWE-190, which describes integer overflow or wraparound conditions, and demonstrates characteristics consistent with memory corruption vulnerabilities. From an ATT&CK perspective, this issue maps to techniques involving memory corruption and privilege escalation through code execution, as the vulnerability could potentially be leveraged to execute arbitrary code on affected systems. Organizations should prioritize updating their ICU4C installations to version 55.1 or later, as this release contains the necessary type consistency fixes. Additionally, implementing input validation and sanitization measures can provide additional defense-in-depth protection against crafted text inputs that might exploit similar vulnerabilities in other components of the system.