MalwareTips
Threat LensFile scan report

Is winmm.dll safe?

Verdict
Malicious

Nineteen of 75 engines flag this unsigned DLL, with six high-trust detections and repeated DLL-hijacking trojan labels from Kaspersky and TrendMicro.

The unsigned winmm.dll is detected by 19 of 75 engines, including six high-trust products. Kaspersky and TrendMicro independently identify DLL-hijacking trojan behavior, while a sandbox observed defense-impairment technique T1562.001; keep the file quarantined and do not load it.

Do not use this component

Quarantine the DLL and do not load or register it. Keep endpoint protection enabled and run a full scan, especially if the file was placed beside or launched with another executable.

Read the full analysis
Saved file evidenceAntivirus consensus
19of 75 flagged
Flagged 19No detection 56
Digital specimenwinmm.dll12b73ffbc82f157b39…65b473aa915396
Size166.5 KB
Code signingUnsigned
SandboxRuntime complete
First seen6d ago
Evidence2 priority signals
19 of 75 antivirus engines flagged the file, including Alibaba and alibabacloud.

Recommended next actions

01

Before using

Do not use it. Quarantine this component with your antivirus, then repair or reinstall the parent software from its official source. Do not delete or replace the component manually.

02

If you already used it

Disconnect from the internet, start a full or offline antivirus scan, then secure important accounts from a clean device.

Chapter 02

Intelligence

The saved assessment, checked against the scan evidence and recorded coverage.

MT AI Engine · Verdict analysis

The reasoning behind this verdict

This section explains the evidence supporting the verdict and keeps conflicting or missing signals visible.

90%Confidence
Very high
Analyst conclusion

The unsigned winmm.dll is detected by 19 of 75 engines, including six high-trust products. Kaspersky and TrendMicro independently identify DLL-hijacking trojan behavior, while a sandbox observed defense-impairment technique T1562.001; keep the file quarantined and do not load it.

Where this verdict could be wrong4 caveats
  • Ten tier-1 engines reported no detection, including Avast, BitDefender, ESET-NOD32, Emsisoft, and Avira.
  • behaviour.hasMaliciousSandboxVerdict=false, and the single completed run recorded no persistence indicators or dropped-file hashes.
  • externalIntel.malwareBazaar.hit=false and externalIntel.yaraify.ruleCount=0, although absence from those sources does not establish benignity.
  • peAnalysis.likelyPacked=false and peAnalysis.highEntropyCode=false, so packing or unusually entropic code does not reinforce the detections.

These are the assessment's weak points. If you believe one applies to your file, report the verdict and we'll re-review it.

Recommended action

Quarantine the DLL and do not load or register it. Keep endpoint protection enabled and run a full scan, especially if the file was placed beside or launched with another executable.

Scan transparency

Coverage & freshness

4 of 5 complete

Complete means the check returned a usable result. It does not mean the file is safe.

  • Antivirus

    Complete

    19 of 75 engines flagged the file.

  • Sandbox

    Complete

    1 isolated runtime environment contributed observations.

  • Network

    Not run

    No contacted-host reputation check is recorded.

    No timestamp recorded

  • YARA

    Complete

    Rule evaluation completed with no recorded matches.

  • External intel

    Complete

    3 of 3 independent reference sources completed.

Chapter 03

Behavior

Plain-English impact first, then the observed runtime evidence.

Runtime flight recorder

Capture complete
  • 1isolated sandbox run
  • 12MITRE ATT&CK techniques
  • 15spawned processes
  • 0network contacts
  • 2filesystem & mutex artifacts

What this file does

Observed actions and their security significance

  • High concern: Attempted to impair or bypass security controls.

  • High concern: Manipulated how the operating system loads code, which can redirect execution.

  • Moderate concern: Contained obfuscated or packed code that makes inspection harder.

  • Moderate concern: Communicated over a common application protocol; malware can use this for command-and-control.

  • Moderate concern: Scans through your files and folders.

  • Moderate concern: Checked the environment for virtualisation or analysis tools.

  • Moderate concern: Checks which security software you have installed.

These are observed capabilities from an isolated analysis. A technique does not prove malicious intent on its own, and the file never ran on your device.

Threat context

How trojans work

A trojan disguises itself as something useful or harmless to trick you into running it. Once open, it does its real job in the background — anything from stealing data to opening a back door or downloading more malware.

Bottom line:The disguise is the whole trick, so a trustworthy-looking name or icon means nothing.

Recorded behavior

Attack story

Runtime observations grouped by analysis stage. Arrows organize the stages; they do not claim chronology or causality.

ObservedDerived

4 recorded facts from one runtime window. Every fact remains independently traceable in Analyst mode.

Chapter 04

Detection & Forensics

Consensus, attribution, signatures, code structure, prevalence, and identity.

Chapter 05

Safety & FAQ

Complete recovery guidance and answers for the next decision.

What to do now

This file is dangerous. Treat it as harmful and remove it.

  1. Recovery step 01

    Don't use this component. Quarantine this component with your antivirus, then repair or reinstall the parent software from its official source. Do not delete or replace the component manually.

  2. Recovery step 02

    If you already used it, disconnect from the internet and start with a full antivirus scan or Microsoft Defender Offline scan. If compromise is suspected or the problem persists, use a reputable second-opinion scanner and follow incident-recovery or clean-reinstall guidance.

  3. Recovery step 03

    If you typed any passwords while it was open, change them from a device you trust.

  4. Recovery step 04

    Reinstall the parent software from the developer's official site instead of replacing this component by itself.

Safety FAQ

Direct answers grounded in the saved verdict and evidence in this report.

8 evidence-based answers
Is winmm.dll malware?
Evidence-based answer
Yes — winmm.dll is malicious. Do not use it. Quarantine this component with your antivirus, then repair or reinstall the parent software from its official source. Do not delete or replace the component manually. 19 of 75 antivirus engines flag it (family: DLLHijack). It behaves as a trojan — malware disguised as something harmless to trick you into running it. If you've already used it, see the removal and recovery steps below.
What is winmm.dll?
Evidence-based answer
winmm.dll is a Windows library or loadable module, about 167 KB. Our analysis identifies it as malicious (family: DLLHijack) — a trojan — malware disguised as something harmless to trick you into running it. Because a file's name and icon can be faked, the safest way to identify it is by its cryptographic hash (below), not its filename.
How many antivirus engines detected winmm.dll?
Evidence-based answer
19 of 75 antivirus engines flagged winmm.dll, 19 of them as outright malicious. The raw count alone does not establish safety or danger; we also weigh which engines flagged it and corroborating behavior, identity, reputation, and rule evidence. The malicious verdict comes from the complete saved evidence, not from this antivirus count by itself.
I already downloaded and used winmm.dll — what should I do?
Evidence-based answer
Act quickly. 1) Disconnect the device from the internet to stop the malware communicating or spreading. 2) Run a full scan with reputable anti-malware software (such as Malwarebytes) and quarantine everything it finds. 3) Change your important passwords from a DIFFERENT, clean device — many threats log keystrokes or steal saved credentials. 4) If you bank or shop on this device, watch closely for fraud and alert your bank. 5) For a confirmed infection, the most reliable fix is to back up your personal files and reinstall the operating system for a clean start.
How do I remove winmm.dll?
Evidence-based answer
To remove winmm.dll: 1) restart into Safe Mode (Safe Mode with Networking if you need to download a tool) so the malware doesn't auto-start. 2) Run a full scan with reputable anti-malware software and let it quarantine or delete the detections. 3) Quarantine this component with your antivirus, then repair or reinstall the parent software from its official source. Do not delete or replace the component manually. 4) Check your browser extensions, startup items, and scheduled tasks for anything unfamiliar. 5) Reboot and scan again to confirm it's gone. If detections keep coming back, a clean operating-system reinstall is the most dependable cure.
What kind of malware is winmm.dll?
Evidence-based answer
winmm.dll is classified as a trojan — malware disguised as something harmless to trick you into running it. Engines attribute it to the DLLHijack family. Knowing the family matters because it tells you the likely impact — data theft, remote control, file encryption, or unwanted ads — and guides the cleanup.
What is the SHA-256 hash of winmm.dll?
Evidence-based answer
The SHA-256 hash of winmm.dll is 12b73ffbc82f157b39bf9c8c83eb6695f723257aae1bab8af765b473aa915396, and its MD5 is fad972f3ab28e0b06ce5d25c863f5019. This hash is the file's unique fingerprint — two files with the same SHA-256 are identical. Use it to confirm you're looking at exactly this file (not just one with the same name) when comparing against antivirus databases or a download's published checksum.
How up to date is this analysis of winmm.dll?
Evidence-based answer
This report reflects the scan run on September 26, 2026. Because a file's hash never changes, the identity of winmm.dll is fixed — but antivirus coverage improves over time, so a file that looks clean today can pick up detections later (and vice-versa). If you need the latest picture, MalwareTips staff can re-run the analysis from scratch.
Chapter 06

Community

Member reviews and reports for this exact file hash.

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The raw file is processed temporarily and is not retained after processing. Its hash and report are public and permanent, so the next person who checks the same file gets an instant answer. Unknown files may be submitted to VirusTotal for analysis. If you ran this file on your computer and are worried, scan your system with an up-to-date antivirus and change critical passwords from a different device.