CVE-2018-0552 in PhishWall Client
Summary
by MITRE
Untrusted search path vulnerability in The installer of PhishWall Client Firefox and Chrome edition for Windows Ver. 5.1.26 and earlier allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2018-0552 represents a critical untrusted search path issue within the PhishWall Client installer for Firefox and Chrome editions on Windows platforms. This flaw affects versions 5.1.26 and earlier, creating a significant security risk that adversaries can exploit to elevate privileges through malicious DLL injection techniques. The vulnerability stems from the installer's failure to properly validate and sanitize the search path used during the installation process, allowing attackers to place malicious dynamic link libraries in directories that are searched before legitimate system locations.
The technical implementation of this vulnerability aligns with CWE-427, which describes uncontrolled search path dependencies where programs search for libraries in insecure locations that can be manipulated by attackers. When the PhishWall Client installer executes, it follows a predictable search order that includes user-writable directories, enabling an attacker to place a malicious DLL with the same name as a legitimate library. This allows the installer to load the attacker-controlled code instead of the intended system library, creating a privilege escalation vector. The attack typically involves placing a Trojan horse DLL in a directory that appears earlier in the Windows search path, such as the current working directory or a directory specified in the PATH environment variable.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential full system compromise and persistent access. An attacker who successfully exploits this vulnerability can execute arbitrary code with the privileges of the installer process, which typically runs with elevated permissions. This creates opportunities for lateral movement within the network, data exfiltration, and establishment of backdoors. The vulnerability is particularly concerning because it affects the installation process itself, meaning that any user with the ability to influence the installation environment can potentially compromise the system. The attack requires minimal user interaction, as the malicious DLL is loaded automatically during the installation process, making it a stealthy and effective vector for exploitation.
Mitigation strategies for CVE-2018-0552 should focus on both immediate remediation and long-term architectural improvements. Organizations should immediately upgrade to PhishWall Client versions that address this vulnerability, as the manufacturer has likely released patches to correct the untrusted search path behavior. System administrators should implement strict access controls on installation directories and ensure that the PATH environment variable does not include user-writable directories in critical positions. The principle of least privilege should be enforced by running installers with minimal required permissions and by employing application whitelisting solutions to prevent unauthorized DLL loading. Additionally, security monitoring should be enhanced to detect unusual DLL loading patterns and unauthorized modifications to installation directories. This vulnerability demonstrates the importance of secure coding practices and proper input validation, particularly when dealing with system-level operations and library loading mechanisms, as outlined in various security frameworks including the ATT&CK framework's technique for privilege escalation through DLL hijacking.