CVE-2016-20059: IObit Malware Fighter Privilege Escalation

CVE-2016-20059 Overview

CVE-2016-20059 is an unquoted service path vulnerability affecting IObit Malware Fighter version 4.3.1. This security flaw exists in the IMFservice and LiveUpdateSvc services, allowing local attackers to escalate privileges on vulnerable systems. When a Windows service path contains spaces and is not properly quoted, attackers can exploit this misconfiguration by placing a malicious executable in a strategic location within the service path, which will be executed with elevated LocalSystem privileges when the service restarts or the system reboots.

Critical Impact

Local privilege escalation to LocalSystem allows attackers to gain complete control over the affected system, potentially compromising sensitive data and enabling persistent access.

Affected Products

• IObit Malware Fighter 4.3.1
• IMFservice component
• LiveUpdateSvc component

Discovery Timeline

• 2026-04-04 - CVE CVE-2016-20059 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2016-20059

Vulnerability Analysis

This vulnerability is classified under CWE-428 (Unquoted Search Path or Element), a well-known Windows service configuration flaw. When Windows services are configured with paths containing spaces that are not enclosed in quotation marks, the operating system's CreateProcess function interprets the path ambiguously. This creates an exploitation opportunity where an attacker can place a malicious executable at an intermediate path location.

For example, if a service is configured with the path C:\Program Files\IObit\Malware Fighter\IMFservice.exe, Windows will attempt to execute in the following order:

1. C:\Program.exe
2. C:\Program Files\IObit\Malware.exe
3. C:\Program Files\IObit\Malware Fighter\IMFservice.exe

An attacker with write access to any of these intermediate locations can drop a malicious payload that will be executed with the service's privileges—in this case, LocalSystem.

Root Cause

The root cause of CVE-2016-20059 is improper service registration in IObit Malware Fighter 4.3.1. The IMFservice and LiveUpdateSvc services were registered in the Windows Service Control Manager (SCM) without proper quotation marks around their executable paths. This configuration oversight, combined with service paths containing spaces (typical of Program Files directories), creates the exploitable condition.

Attack Vector

The attack requires local access to the system and write permissions to at least one directory in the unquoted service path hierarchy. The attacker must:

1. Identify the vulnerable unquoted service path using tools like wmic service get name,displayname,pathname,startmode or by querying the Windows registry
2. Verify write access to an exploitable intermediate directory location
3. Create a malicious executable named appropriately to intercept the service path resolution (e.g., Malware.exe placed in C:\Program Files\IObit\)
4. Wait for or trigger a service restart or system reboot

Upon service initialization, the malicious executable runs with LocalSystem privileges, granting the attacker complete control over the system.

Detection Methods for CVE-2016-20059

Indicators of Compromise

• Unexpected executable files in intermediate path locations such as C:\Program Files\IObit\Malware.exe or C:\Program.exe
• Unusual process execution with LocalSystem privileges from non-standard paths
• Registry modifications to service ImagePath values
• Suspicious service restart events coinciding with new file creation

Detection Strategies

• Query Windows services for unquoted paths containing spaces using WMI commands: wmic service get name,pathname | findstr /i "IObit"
• Monitor for file creation events in C:\Program Files\IObit\ directory for executables not signed by IObit
• Implement endpoint detection rules to alert on execution of unsigned binaries from Program Files subdirectories with LocalSystem privileges
• Use SentinelOne's Storyline technology to correlate service restarts with suspicious child process creation

Monitoring Recommendations

• Enable Windows Security Event auditing for service state changes (Event ID 7036) and new service installations (Event ID 7045)
• Configure file integrity monitoring on directories within the IObit installation path
• Deploy behavioral analysis to detect privilege escalation patterns following service restarts
• Monitor for CreateProcess calls from service executables spawning unexpected child processes

How to Mitigate CVE-2016-20059

Immediate Actions Required

• Audit all IObit Malware Fighter installations for version 4.3.1 and upgrade to the latest available version
• Manually quote the service paths in the Windows registry for IMFservice and LiveUpdateSvc if an upgrade is not immediately possible
• Remove any suspicious executables from intermediate path locations
• Restrict write permissions on C:\Program Files\IObit\ to administrators only

Patch Information

IObit has released updated versions of Malware Fighter that address this unquoted service path vulnerability. Users should upgrade to the latest version available from the IObit Download Center. Additional technical details about this vulnerability can be found in the Exploit-DB #40525 advisory and the VulnCheck Advisory on IObit.

Workarounds

• Manually fix the registry entries by adding quotation marks around the service ImagePath values for IMFservice and LiveUpdateSvc
• Restrict NTFS permissions on the C:\Program Files\IObit\ directory to prevent non-administrative users from creating files
• Consider implementing application whitelisting to prevent execution of unauthorized binaries in the IObit installation directory
• Use Group Policy to enforce service path quoting standards across the enterprise

# Registry fix for unquoted service path (run as Administrator)
# Fix IMFservice path
reg add "HKLM\SYSTEM\CurrentControlSet\Services\IMFservice" /v ImagePath /t REG_EXPAND_SZ /d "\"C:\Program Files\IObit\Malware Fighter\IMFservice.exe\"" /f

# Fix LiveUpdateSvc path
reg add "HKLM\SYSTEM\CurrentControlSet\Services\LiveUpdateSvc" /v ImagePath /t REG_EXPAND_SZ /d "\"C:\Program Files\IObit\Malware Fighter\LiveUpdateSvc.exe\"" /f