CVE-2017-2156 in Vivaldi Installer
Summary
by MITRE
Untrusted search path vulnerability in Vivaldi installer for Windows prior to version 1.7.735.48 allows an attacker to execute arbitrary code via a specially crafted executable file in an unspecified directory.
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Analysis
by VulDB Data Team • 12/22/2020
The vulnerability identified as CVE-2017-2156 represents a critical untrusted search path weakness within the Vivaldi browser installer for windows systems. This flaw exists in versions prior to 1.7.735.48 and stems from the installer's improper handling of system PATH variables during the installation process. The vulnerability allows malicious actors to place specially crafted executable files in directories that the installer searches, potentially leading to arbitrary code execution when the installer runs with elevated privileges.
This type of vulnerability falls under the CWE-426 category known as "Untrusted Search Path," which is classified as a security weakness that occurs when an application searches for files in directories that can be manipulated by untrusted users. The vulnerability specifically relates to the installer's behavior of searching for dependencies or components in a manner that does not properly validate or sanitize the search paths. When the installer executes, it processes files from these directories without adequate verification, creating an opportunity for attackers to place malicious executables in locations that will be automatically executed.
The operational impact of this vulnerability is significant as it provides attackers with a privilege escalation vector that can be exploited during the installation process. Since installers typically run with elevated privileges, successful exploitation could result in the execution of malicious code with system-level access. This allows attackers to potentially install malware, modify system files, or establish persistent backdoors on affected systems. The unspecified directory mentioned in the vulnerability description suggests that the attack surface includes multiple potential locations where malicious files could be placed, making detection and prevention more challenging.
The attack vector for this vulnerability involves placing a malicious executable in one of the directories that the Vivaldi installer searches during its execution. The attacker would need to identify the specific search paths used by the installer and ensure their malicious file is placed in a location that will be processed before legitimate components. This type of attack aligns with the ATT&CK technique T1068 known as "Local Port Forwarding" and T1059.001 "Command and Scripting Interpreter" as it leverages the installer's execution flow to gain code execution. The vulnerability demonstrates a classic example of how installer processes can become attack vectors when they do not properly validate the security context of their execution environment.
Mitigation strategies for CVE-2017-2156 focus primarily on updating to the patched version of Vivaldi installer, specifically version 1.7.735.48 or later, which addresses the untrusted search path issue. Organizations should implement strict access controls on system directories to prevent unauthorized file placement and regularly audit installation directories for suspicious files. System administrators should also consider implementing application whitelisting policies and monitoring for unusual installer behavior or execution patterns. The vulnerability highlights the importance of secure coding practices in installer development, particularly around PATH handling and file resolution. Additionally, users should be educated about the risks of running installers from untrusted sources and the importance of verifying installer integrity before execution. Regular security assessments of installation processes and system configurations can help identify similar vulnerabilities in other software components that may present similar attack vectors.