CVE-2021-28646
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn insecure file permissions vulnerability in Trend Micro Apex One, Apex One as a Service and OfficeScan XG SP1 could allow a local attacker to take control of a specific log file on affected installations.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is a local privilege escalation vulnerability where insecure file permissions on a specific log file in Trend Micro Apex One, Apex One as a Service, and OfficeScan XG SP1 allow a local authenticated attacker to take control of that log file. An attacker with local access could potentially modify the log file's contents, which may lead to further compromise depending on how the log file is processed by the application.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 2019= xgCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify installed Trend Micro product and versionCheck the installed version of Trend Micro Apex One, Apex One as a Service, or OfficeScan XG SP1. This can typically be found in Add/Remove Programs, the product console under About, or by querying the installation directory for version information.Affected if The installed version matches Apex One 2019 or OfficeScan XG (or XG SP1)
-
Locate the affected log fileIdentify the log files used by the Trend Micro security product. Common locations include the product's log directory (such as %ProgramFiles%\Trend Micro\Apex One\PCCSRV\Log or similar paths under the product installation folder).Affected if The product is installed and log files exist in the product directory
-
Check file permissions on the log file(s)Right-click the log file(s), select Properties, then view the Security tab. Alternatively, use the command 'icacls <filename>' from an elevated command prompt to view the Access Control List (ACL) permissions.Affected if Users without administrative privileges are granted Write or Full Control permissions to the log file
-
Verify if unprivileged users can modify log contentsFrom a standard (non-admin) user account, attempt to open the log file in a text editor and try to save modifications, or use 'icacls' to confirm Write permission exists for authenticated users or specific user groups.Affected if Non-administrative user accounts have Write or Modify permissions on the log file, allowing them to alter its contents
A user is affected if they have Apex One 2019 or OfficeScan XG installed AND the product's log file(s) grant Write or Modify permissions to unprivileged (non-admin) user accounts.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataRemediate by correcting file permissions on the affected log file(s) to remove excessive write access for unprivileged users. Verify that only appropriate system or administrative accounts have write permissions.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-28646 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-28646 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data