{"id":"CVE-2020-24557","kind":"vulnerability","aliases":["CVE-2020-24557"],"related":[],"title":"Trend Micro Apex One, OfficeScan, and Worry-Free Business Security: Trend Micro Multiple Products Improper Access Control Vulnerability","description":"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.","summary":"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.","severity":"high","cvss":7.8,"epss":0.02666,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","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"],"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.\nNote: 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).\nUntil patched, restrict local low-privilege code execution on endpoints running the product.","status":"open","published_at":"2020-09-01T19:15:11+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T20:29:41+00:00","updated_at":"2026-10-23T20:29:41+00:00","category":"vendor","confidence":0.7,"triage":{"at":"2026-10-23T20:29:41Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Apex One or Worry-Free Business Security to a fixed build from Trend Micro (fixed version unknown from sources).\nUntil patched, restrict local low-privilege code execution on endpoints running the product.","summary":"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.","category":"vendor","who_cares":["windows","trend-micro","apex-one","worry-free-business-security","officescan","endpoints"],"confidence":0.7,"analyst_note":"Find the fixed Trend Micro build number and the Windows-side mitigation guidance; source URLs given do not name a fixed version.","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.\nunknown for the exact file or registry path to inspect.\nNote: the description says Windows 10 version 1909 (OS Build 18363.719) mitigates hard links, so older Windows builds are the exposed ones.","needs_analyst":true,"not_affected_if":["managed-hosting","non-windows-endpoints","patched-build"],"severity_if_unknown":"high"},"cost_usd":0.000477,"input_tokens":2251,"output_tokens":504,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2020':21A,24A '-24557':22A,25A '10':193C '10.0':63B,130C '18363.719':189C '1909':186C 'abil':165C 'abus':87B,150C 'access':17A,70B 'affect':201C 'allow':136C 'alreadi':94B 'and':31A 'apex':3A,28A,38B,55B,122C 'apex-on':37B 'attack':92B,138C,160C 'attain':156C 'build':188C 'busi':10A,51B,61B,128C 'business':35A 'cisa':109B 'code':99B,171C 'contain':67B 'control':18A,71B 'cve':20A,23A 'disabl':84B,146C 'endpoint':40B 'escal':104B,158C 'execut':167C 'exploit':41B,113B,179C 'first':162C 'flaw':72B 'folder':81B,144C 'free':9A,34A,50B,60B,127C 'function':90B,154C 'hard':195C 'higher':106B 'improp':16A,69B 'let':74B 'link':196C 'list':110B 'local':76B 'low':97B,169C 'low-privileg':96B,168C 'machin':102B 'manipul':78B,140C 'may':135C 'micro':2A,13A,27A,45B,54B,121C 'microsoft':133C,191C 'mitig':194C 'multipl':14A 'must':161C 'note':183C 'obtain':163C 'officescan':5A,30A,42B 'one':4A,29A,39B,56B,123C 'order':177C 'os':187C 'particular':142C 'pleas':182C 'previous':198C 'privileg':98B,107B,157C,170C 'product':15A,80B,143C 'run':95B 'secur':11A,52B,62B,85B,129C,148C 'security':36A 'sp1':64B,131C 'specif':152C 'system':175C 'target':174C 'temporarili':83B,149C 'trend':1A,12A,26A,44B,53B,120C 'trend-micro':43B 'user':77B 'vendor':46B 'version':185C,199C 'vulner':19A,118C,181C 'wild':116B 'window':47B,66B,89B,134C,153C,192C 'worri':8A,49B,59B,126C 'worry':33A 'worry-fre':7A,58B,125C 'worry-free':32A 'worry-free-business-secur':48B","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2020-09-01T19:15:11+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2020-24557","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-24557","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T15:39:44+00:00","note":null},{"source":"epss","external_id":"CVE-2020-24557","url":"https://api.first.org/data/v1/epss?cve=CVE-2020-24557","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2020-24557","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-24557","severity":null,"published_at":"2020-09-01T19:15:11+00:00","modified_at":"2026-06-17T03:05:45+00:00","first_seen_at":"2026-10-23T19:35:23+00:00","fetched_at":"2026-10-23T19:35:23+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}