---
id: "CVE-2020-24557"
kind: "vulnerability"
aliases: ["CVE-2020-24557"]
title: "Trend Micro Apex One, OfficeScan, and Worry-Free Business Security: Trend Micro Multiple Products Improper Access Control Vulnerability"
severity: "high"
cvss: 7.8
epss: 0.02666
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Trend Micro Apex One, OfficeScan, and Worry-Free Business Security", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["apex-one", "endpoints", "exploited", "officescan", "trend-micro", "vendor", "windows", "worry-free-business-security"]
not_affected_if: ["managed-hosting", "non-windows-endpoints", "patched-build"]
published_at: "2020-09-01T19:15:11+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T20:29:41+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-24557", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2020-24557", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-24557", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Trend Micro Apex One, OfficeScan, and Worry-Free Business Security: Trend Micro Multiple Products Improper Access Control Vulnerability

Trend Micro Apex One and Worry-Free Business Security 10.0 SP1 on Windows contain an improper access control flaw that lets a local user manipulate a product folder to temporarily disable security and abuse a Windows function. An attacker who already runs low-privileged code on the machine can escalate to higher privileges, and CISA lists it as exploited in the wild.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Trend Micro Apex One, OfficeScan, and Worry-Free Business Security affected ? fixed ?

## How to check

Check the installed Apex One or Worry-Free Business Security version on Windows endpoints and confirm it is not 10.0 SP1 with a pre-fix build.
Note: the description says Windows 10 version 1909 (OS Build 18363.719) mitigates hard links, so older Windows builds are the exposed ones.

## Fix

Upgrade Apex One or Worry-Free Business Security to a fixed build from Trend Micro (fixed version unknown from sources).
Until patched, restrict local low-privilege code execution on endpoints running the product.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-24557
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2020-24557
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2020-24557

## From the sources

A vulnerability in Trend Micro Apex One and Worry-Free Business Security 10.0 SP1 on Microsoft Windows may allow an attacker to manipulate a particular product folder to disable the security temporarily, abuse a specific Windows function and attain privilege escalation. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. Please note that version 1909 (OS Build 18363.719) of Microsoft Windows 10 mitigates hard links, but previous versions are affected.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_