CVE-2016-4819 in DX Library for Borland C++
Summary
by MITRE
The printfDx function in Takumi Yamada DX Library for Borland C++ 3.13f through 3.16b, DX Library for Gnu C++ 3.13f through 3.16b, and DX Library for Visual C++ 3.13f through 3.16b allows remote attackers to execute arbitrary code via a crafted string.
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Analysis
by VulDB Data Team • 01/30/2019
The vulnerability identified as CVE-2016-4819 represents a critical buffer overflow flaw within the printfDx function of the Takumi Yamada DX Library across multiple compiler environments including Borland C++, GNU C++, and Microsoft Visual C++. This library, widely used for graphics and multimedia applications, contains a dangerous flaw in its formatted string handling mechanism that can be exploited by remote attackers to execute arbitrary code on affected systems. The vulnerability affects versions ranging from 3.13f through 3.16b, indicating a prolonged period of exposure across multiple releases. The printfDx function, designed to handle formatted output for debugging and logging purposes, fails to properly validate input string lengths, creating an exploitable condition where maliciously crafted strings can overwrite adjacent memory locations.
The technical implementation of this vulnerability stems from improper bounds checking within the printfDx function's string processing logic. When the function receives a crafted input string, it fails to enforce safe buffer limits during format string expansion, allowing attackers to manipulate memory layout through carefully constructed input sequences. This flaw directly maps to CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which addresses stack-based buffer overflow scenarios. The vulnerability exploits the fundamental weakness in format string handling where the function does not properly validate the length of input strings against the allocated buffer space, creating a path for memory corruption that can be leveraged for code execution. The attack vector is particularly dangerous as it operates over remote network connections, making exploitation possible without physical access to target systems.
The operational impact of CVE-2016-4819 extends beyond simple code execution capabilities, as it provides attackers with complete system compromise potential through various attack techniques documented in the MITRE ATT&CK framework. The vulnerability enables adversaries to perform code injection attacks targeting the affected applications, potentially leading to privilege escalation and persistent access. Attackers can leverage this flaw to gain unauthorized access to systems running vulnerable versions of the DX Library, making it particularly dangerous for networked applications that process user input through the printfDx function. The remote exploitation capability means that attackers can target systems without requiring local access, making this vulnerability particularly attractive for large-scale attacks against applications that utilize the affected library. Organizations using these legacy libraries face significant risk as the vulnerability can be exploited through various attack surfaces including web applications, network services, and desktop applications that depend on the affected library components.
Mitigation strategies for CVE-2016-4819 require immediate action to address the root cause through comprehensive library updates and code modifications. Organizations should prioritize upgrading to patched versions of the Takumi Yamada DX Library, as no official patches exist for the vulnerable versions, making the upgrade to newer, secure releases the primary remediation path. System administrators must conduct thorough inventory assessments to identify all applications utilizing the affected library versions, implementing network segmentation and access controls to limit potential attack vectors. The implementation of input validation controls and strict format string handling practices within applications can provide additional defensive layers against exploitation attempts. Security monitoring should be enhanced to detect suspicious string patterns and unusual network behavior that might indicate exploitation attempts, while also implementing application whitelisting to prevent execution of untrusted code. Regular security assessments and vulnerability scanning should be conducted to identify similar vulnerabilities within legacy codebases, as the presence of one such flaw often indicates broader security weaknesses in older software components. The vulnerability underscores the importance of maintaining up-to-date software libraries and implementing robust security practices throughout the software development lifecycle.