CVE-2018-0599 in Visual C++ Redistributable
Summary
by MITRE
Untrusted search path vulnerability in the installer of Visual C++ Redistributable allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 02/22/2020
The vulnerability identified as CVE-2018-0599 represents a critical untrusted search path weakness within the installer component of Microsoft Visual C++ Redistributable packages. This flaw resides in the installation process where the system fails to properly validate the origins of dynamically loaded libraries, creating an exploitable condition that can be leveraged by malicious actors to elevate privileges. The vulnerability specifically affects the installer's behavior when resolving dynamic link library dependencies, allowing an attacker to place a malicious DLL in a directory that gets searched before the legitimate system directories. This issue falls under the broader category of CWE-426 Untrusted Search Path, which is classified as a privilege escalation vector when the search path is manipulated to load unauthorized code.
The technical implementation of this vulnerability exploits the Windows DLL search order mechanism, where the operating system searches for required libraries in a specific sequence including the current working directory, system directories, and then the PATH environment variable. When the Visual C++ Redistributable installer runs with elevated privileges, an attacker who can write to a directory in the search path can place a malicious DLL that matches the name of a legitimate library required by the installer. This malicious DLL will be loaded and executed with the elevated privileges of the installer process, potentially allowing the attacker to execute arbitrary code with system-level access. The vulnerability is particularly dangerous because it leverages the legitimate installer process, making the attack less suspicious and more likely to succeed in environments with strict security controls.
The operational impact of CVE-2018-0599 extends beyond simple privilege escalation, as it can be used as a foundational attack vector for more sophisticated compromise techniques. Attackers can leverage this vulnerability to establish persistent access, deploy additional malware, or conduct lateral movement within a network. The attack requires minimal privileges to prepare the malicious DLL in the target directory, but the actual exploitation results in system-level compromise. This vulnerability is particularly concerning in enterprise environments where Visual C++ Redistributable packages are frequently deployed through automated processes or group policies. The impact is amplified when considering that many applications depend on these redistributables, making the attack surface larger than initially apparent. According to the MITRE ATT&CK framework, this vulnerability maps to T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, demonstrating how the initial compromise can lead to broader system control.
Mitigation strategies for CVE-2018-0599 should focus on both immediate remediation and long-term architectural improvements. Microsoft has addressed this vulnerability through security updates that modify the installer behavior to use more secure search paths and implement proper DLL loading mechanisms. Organizations should ensure all systems have the latest Visual C++ Redistributable updates applied, particularly those running older versions such as 2013, 2015, 2017, and 2019. Additional protective measures include implementing application whitelisting policies, monitoring for suspicious DLL loading activities, and ensuring that system directories are properly secured against unauthorized modifications. The vulnerability highlights the importance of secure coding practices and proper DLL loading mechanisms as outlined in the CWE guidelines, which recommend using absolute paths for dynamic library loading and implementing proper privilege separation. Security teams should also consider implementing process monitoring to detect when installers or other system utilities load unexpected DLLs, as this can serve as an indicator of exploitation attempts.