CVE-2018-25328: VX Search Buffer Overflow Vulnerability

CVE-2018-25328 Overview

CVE-2018-25328 is a local stack-based buffer overflow vulnerability in VX Search 10.6.18. The flaw exists in the application's directory field input handler, which fails to validate the length of user-supplied strings before copying them into a fixed-size stack buffer. Attackers can craft a malicious input file containing 271 bytes of junk data followed by a return address to overwrite the saved instruction pointer (EIP). Successful exploitation allows arbitrary code execution under the privileges of the VX Search process. The weakness is categorized under [CWE-120] (Buffer Copy without Checking Size of Input).

Critical Impact
Local attackers can overwrite the instruction pointer and execute arbitrary code with the privileges of the VX Search application by loading a crafted configuration file.

Affected Products

VX Search 10.6.18
VX Search prior versions sharing the vulnerable directory-field parser
Deployments importing externally supplied VX Search configuration or task files

Discovery Timeline

2026-05-17 - CVE-2018-25328 published to NVD
2026-05-18 - Last updated in NVD database

Technical Details for CVE-2018-25328

Vulnerability Analysis

VX Search is a file search utility for Windows that allows users to define search tasks with directory paths and filters. The vulnerable code path processes the directory field of a search task without enforcing a maximum input length. When a string longer than the allocated buffer is supplied, the excess bytes overwrite adjacent stack data, including the saved return address.

The published proof-of-concept on Exploit-DB (entry 44494) demonstrates that 271 bytes of padding place the next four bytes directly over the saved EIP on a 32-bit build. By placing a pointer to a controlled gadget or shellcode at that offset, an attacker redirects execution. The vulnerability is local because the trigger requires the victim to open a crafted task or input file inside the application.

Root Cause

The root cause is missing bounds checking in the routine that copies the directory string from the input file into a fixed-size stack buffer. The function uses an unsafe string copy operation without validating length against the destination buffer size, satisfying the conditions described in [CWE-120].

Attack Vector

Exploitation requires local access and user interaction to load the malicious file into VX Search. An attacker delivers a crafted task or configuration file containing a 271-byte filler sequence followed by a 4-byte target address and optional shellcode. When the application parses the directory field, the overflow occurs and execution transfers to attacker-controlled memory.

No authenticated remote vector is documented. See the Exploit-DB entry 44494 and the VulnCheck Advisory for VX-Search for the original technical write-up.

Detection Methods for CVE-2018-25328

Indicators of Compromise

VX Search task or input files containing unusually long directory strings, particularly sequences of 270+ repeating characters followed by non-printable bytes
Unexpected child processes spawned by the VX Search executable, such as cmd.exe, powershell.exe, or rundll32 invocations
VX Search process crashes with access violations referencing addresses outside loaded modules, suggesting failed exploitation attempts

Detection Strategies

Hunt for VX Search process executions immediately followed by shell or scripting interpreter creation in endpoint telemetry
Inspect VX Search configuration directories for files with binary content embedded in directory fields
Correlate application crash events in the Windows Application event log with VX Search faulting module data

Monitoring Recommendations

Enable command-line and parent-child process logging on hosts running VX Search
Capture file integrity events for VX Search task files and user-writable configuration paths
Alert on memory-protection violations originating from the VX Search image

How to Mitigate CVE-2018-25328

Immediate Actions Required

Restrict who can write VX Search task and configuration files on shared systems, limiting input sources to trusted administrators
Run VX Search under a least-privilege user account to reduce the blast radius of successful exploitation
Block import of VX Search task files received from external or untrusted sources
Audit endpoints for installed VX Search versions and inventory exposure to version 10.6.18

Patch Information

No fixed version is identified in the published advisory data. Consult the VXSearch Homepage and the VulnCheck Advisory for VX-Search for vendor updates. If a current release that addresses the directory-field parsing issue is available, upgrade affected systems. Otherwise, consider replacing the application or applying the workarounds below.

Workarounds

Enable Windows Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) system-wide to raise the cost of return-address overwrites
Apply Microsoft Exploit Protection or equivalent mitigations to the VX Search executable, including mandatory ASLR and stack protection
Use application allowlisting to prevent VX Search from launching child interpreters such as cmd.exe or powershell.exe
Remove VX Search from systems where it is not operationally required

bash

# Configuration example: apply Exploit Protection settings to VX Search via PowerShell
Set-ProcessMitigation -Name "vxsearch.exe" `
  -Enable DEP,EmulateAtlThunks,ForceRelocateImages,BottomUp,HighEntropy,StrictHandle,SEHOP