CVE-2017-12312 in Immunet Antimalware Installer
Summary
by MITRE
An untrusted search path (aka DLL Preloading) vulnerability in the Cisco Immunet antimalware installer could allow an authenticated, local attacker to execute arbitrary code via DLL hijacking if a local user with administrative privileges executes the installer in the current working directory where a crafted DLL has been placed by an attacker. The vulnerability is due to incomplete input validation of path and file names of a DLL file before it is loaded. An attacker could exploit this vulnerability by creating a malicious DLL file and installing it in a specific system directory. A successful exploit could allow the attacker to execute commands on the underlying Microsoft Windows host with privileges equivalent to the SYSTEM account. An attacker would need valid user credentials to exploit this vulnerability. Cisco Bug IDs: CSCvf23928.
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Analysis
by VulDB Data Team • 12/07/2019
The vulnerability identified as CVE-2017-12312 represents a critical untrusted search path issue within Cisco Immunet antimalware installer that falls under the CWE-426 weakness category, specifically addressing the dangerous practice of DLL preloading. This vulnerability exists in the installer component of Cisco Immunet, which is designed to provide antimalware protection for enterprise environments. The flaw manifests when the installer process fails to properly validate or sanitize the paths and filenames of dynamic link libraries that it attempts to load during execution. The installer's improper handling of DLL loading mechanisms creates an exploitable condition where an attacker can manipulate the search path to load malicious code instead of legitimate system libraries.
The operational impact of this vulnerability extends beyond simple privilege escalation as it allows for full system compromise when exploited by an authenticated local attacker. The vulnerability requires administrative privileges to be successfully exploited, meaning that an attacker must first obtain valid user credentials through other means such as credential theft, social engineering, or prior compromise of a system. Once these credentials are obtained, the attacker can execute the malicious installer in the current working directory where they have placed a crafted DLL file. This approach leverages the Windows DLL search order mechanism, where the system searches for required libraries in a specific sequence including the current working directory before checking system directories, making this attack vector particularly effective. The successful exploitation results in code execution with SYSTEM privileges, which represents the highest level of access possible on a Windows system and allows complete control over the target host.
The technical exploitation of this vulnerability follows established patterns documented in the ATT&CK framework under the T1059 technique for command and script interpreter, specifically targeting the Windows Installer service and DLL loading mechanisms. The vulnerability's root cause lies in the incomplete input validation of path and filename parameters, which directly maps to CWE-78 and CWE-88 categories that address command injection and path traversal issues. Attackers can create malicious DLL files with names that match legitimate system libraries, placing them in directories where the installer will search first, effectively hijacking the loading process. This type of attack is particularly dangerous because it can bypass many traditional security controls and is often difficult to detect through standard network monitoring or endpoint protection solutions. The vulnerability affects Cisco Immunet installations and demonstrates the critical importance of proper input validation and secure coding practices in installer and setup programs, as these components often run with elevated privileges and have access to critical system resources.
Mitigation strategies for this vulnerability should focus on implementing proper path validation and secure DLL loading practices within the installer components. Organizations should ensure that all installer programs validate and sanitize all input paths and filenames before attempting to load dynamic libraries. The recommended approach includes using absolute paths for all DLL references, implementing proper DLL search path controls, and ensuring that installer programs run with the minimum necessary privileges. Additionally, system administrators should monitor for unauthorized DLL placement in directories where installers execute, particularly in shared or writable directories. The vulnerability underscores the importance of following secure coding guidelines and conducting thorough security testing of installer components, as these programs often serve as attack vectors due to their elevated execution privileges and access to system resources. Regular security updates and patch management processes should be implemented to address such vulnerabilities promptly, as the window of opportunity for exploitation remains open until the vulnerability is properly mitigated through code-level fixes or administrative controls.