CVE-2018-25365: PCViewer vt1000 Path Traversal Flaw

CVE-2018-25365 Overview

CVE-2018-25365 is a directory traversal vulnerability [CWE-22] affecting PCViewer vt1000, a file management utility. The flaw allows unauthenticated remote attackers to read arbitrary files on the host system by submitting relative path sequences in HTTP GET requests. Attackers can traverse outside the intended web root using sequences such as ../../../../etc/passwd to access sensitive operating system files. The vulnerability requires no authentication, no user interaction, and is exploitable over the network. A public exploit has been published to Exploit-DB, increasing the risk of opportunistic scanning and exploitation.

Critical Impact
Unauthenticated remote attackers can read arbitrary files on systems running PCViewer vt1000, exposing credentials, configuration data, and other sensitive information.

Affected Products

PCViewer vt1000 (file management utility distributed via Softpedia)
Systems running the embedded HTTP service of PCViewer vt1000
Endpoints exposing PCViewer vt1000 to untrusted networks

Discovery Timeline

2026-05-25 - CVE-2018-25365 published to NVD
2026-05-26 - Last updated in NVD database

Technical Details for CVE-2018-25365

Vulnerability Analysis

The vulnerability resides in the HTTP request handler of PCViewer vt1000. The application fails to canonicalize or sanitize path components supplied through GET request URIs. When a client submits a request containing ../ sequences, the server resolves the path relative to its serving directory without restricting traversal upward through the filesystem hierarchy. This allows an attacker to escape the intended document root and reach any file the service process can read. The vulnerability is classified under [CWE-22] (Improper Limitation of a Pathname to a Restricted Directory).

Root Cause

The root cause is missing input validation on the path portion of incoming HTTP requests. The application accepts relative path traversal tokens (../) and concatenates the user-supplied path to its base directory without normalization. There is no allowlist of permitted resources, no chroot-style confinement, and no authentication check on the file-serving endpoint.

Attack Vector

Exploitation requires only network access to the PCViewer vt1000 HTTP service. An attacker sends a crafted GET request containing a long sequence of ../ tokens followed by an absolute target path, for example a request to /../../../../../../../../../../../../etc/passwd. The server reads the targeted file from disk and returns its contents in the HTTP response. No credentials or session state are required. The public proof-of-concept is documented in Exploit-DB #45248 and the Vulncheck Advisory for PC Viewer.

Detection Methods for CVE-2018-25365

Indicators of Compromise

HTTP GET requests containing repeated ../ or URL-encoded %2e%2e%2f sequences in the URI path
Requests targeting sensitive file paths such as /etc/passwd, /etc/shadow, boot.ini, or win.ini
Outbound HTTP responses from PCViewer vt1000 hosts containing recognizable system file signatures (e.g., root:x:0:0)
Access log entries for the PCViewer HTTP service originating from unexpected external IP addresses

Detection Strategies

Inspect web server and proxy logs for path traversal patterns including encoded variants (..%2f, %2e%2e/, ..\)
Deploy IDS/IPS signatures that flag traversal sequences against the PCViewer vt1000 listening port
Correlate file read events on sensitive system files with concurrent inbound HTTP activity to identify successful exploitation
Run authenticated network scans to identify PCViewer vt1000 instances exposed to internal or external networks

Monitoring Recommendations

Forward PCViewer host logs and network telemetry to a centralized analytics platform for traversal pattern matching
Alert on any read access to /etc/passwd, /etc/shadow, or Windows SAM-related files from non-administrative processes
Monitor for HTTP 200 responses from PCViewer vt1000 endpoints that return file contents larger than typical UI responses

How to Mitigate CVE-2018-25365

Immediate Actions Required

Remove PCViewer vt1000 from production systems or restrict its HTTP listener to loopback only
Block inbound network access to the PCViewer vt1000 service port at perimeter and host firewalls
Audit hosts for the presence of PCViewer vt1000 using software inventory tools and uninstall where not required
Rotate any credentials or secrets stored in files that may have been exposed through traversal

Patch Information

No vendor patch is referenced in the available advisories. PCViewer vt1000 is distributed as a third-party utility through Softpedia, and no fixed version is identified in the NVD entry or in the Vulncheck Advisory for PC Viewer. Organizations should treat the software as unsupported and migrate to a maintained alternative.

Workarounds

Uninstall PCViewer vt1000 and replace it with a maintained file management tool that receives security updates
Restrict the service to bind only to 127.0.0.1 if removal is not immediately possible
Enforce network segmentation so the PCViewer host cannot be reached from user or untrusted network segments
Apply host-based ACLs that deny the PCViewer process read access to sensitive system files where the operating system permits such restrictions

bash

# Configuration example: block inbound access to the PCViewer HTTP port (Linux iptables)
iptables -A INPUT -p tcp --dport 8080 -s 127.0.0.1 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP