CVE-2020-24557

Exp

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.

Published: 2020-09-01 Last update: 2025-10-31 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-24557 is rated Critical Active Threat (86.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.64%). CISA KEV confirms active exploitation (added 2021-11-03) affecting Trend Micro / Apex One, OfficeScan, and Worry-Free Business Security. Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2020-24557

Name: Trend Micro Multiple Products Improper Access Control Vulnerability · CISA KEV detail

Exploit added: 2021-11-03

Action due: 2022-05-03

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2020-24557

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.88% 2.64% +0.76%
2 2025-11-21 6.88% 1.88% -5.00%
3 2025-11-18 — 6.88% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-24557

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
7.2 2.0 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 3.9 10.0 [email protected]

Weakness enumeration for CVE-2020-24557

Affected software / configurations for CVE-2020-24557

Vendor Product Version Raw CPE
trendmicro apex_one — cpe:2.3:a:trendmicro:apex_one:-:*:*:*:saas:*:*:*
trendmicro apex_one 2019 cpe:2.3:a:trendmicro:apex_one:2019:*:*:*:*:*:*:*
trendmicro worry-free_business_security 10.0 cpe:2.3:a:trendmicro:worry-free_business_security:10.0:sp1:*:*:*:*:*:*

References for CVE-2020-24557

cvelogic Threat Intelligence