Is tb_grumblebum_2_7.dll safe?
Single low-trust engine flags an unsigned 12-year-old DLL whose sandbox activity maps to T1055 but lacks tier-1 corroboration.
75 engines scanned the file; only Cynet (low-trust) returned a malicious label. No tier-1 detections, no signed publisher, and no external-intel hits exist. Sandbox recorded T1055 process-injection behaviour, yet the overall profile aligns with a long-standing, low-signal file rather than confirmed malware.
a9273bc1267bc43197…05ecd7a8d3f74dRecommended next actions
Before using
Use it only as part of software obtained from the developer's official site or another source you independently trust.
If you already used it
Keep normal device protection enabled and stop if the file behaves unexpectedly.
Intelligence
The saved assessment, checked against the scan evidence and recorded coverage.
The reasoning behind this verdict
This section explains the evidence supporting the verdict and keeps conflicting or missing signals visible.
75 engines scanned the file; only Cynet (low-trust) returned a malicious label. No tier-1 detections, no signed publisher, and no external-intel hits exist. Sandbox recorded T1055 process-injection behaviour, yet the overall profile aligns with a long-standing, low-signal file rather than confirmed malware.
The engine distribution shows a textbook low-trust-only pattern: 1 malicious out of 75 total, zero tier-1 flags, and onlyLowTrustFlagging=true. The unsigned status and absence of signer history are neutral for a DLL of this age. Sandbox evidence of T1055 is noted but explicitly caveated by the heuristic itself as not proving intent. Medium prevalence over 18 submitters and zero external-intel matches further reduce the likelihood of active malice.
What We Detected
One low-trust engine (Cynet) assigned a generic malicious score; the remaining 74 engines, including all 17 tier-1 engines, remained silent or timed out. The file is an unsigned Win32 DLL first seen in 2010.
Threat Behavior
Sandbox execution mapped observed actions to MITRE T1055 (Process Injection) and recorded multiple WerFault and rundll32 command lines. No malicious child files, no C2 domains, and no YARA or CIRCL hits were found.
What To Do Now
Keep Windows Defender and other endpoint protection enabled. If the DLL is required by a specific application, restrict its use to that application’s directory and monitor for unexpected child processes.
Where this verdict could be wrong1 caveat
- Sandbox observed T1055 process-injection activity and wrote multiple WER temp/report files; while not conclusive, this is a legitimate counter-signal to the otherwise clean engine profile.
These are the assessment's weak points. If you believe one applies to your file, report the verdict and we'll re-review it.
- Zero tier-1 malicious detections
- Medium prevalence over 12 years
- No external intelligence hits
- Unsigned DLL
- Sandbox mapped T1055 process-injection activity
The sample can be treated as safe for normal use; continue running up-to-date antivirus.
Coverage & freshness
Complete means the check returned a usable result. It does not mean the file is safe.
Antivirus
Complete1 of 75 engines flagged the file.
Sandbox
Complete1 isolated runtime environment contributed observations.
Network
Not runNo contacted-host reputation check is recorded.
No timestamp recordedYARA
Complete1 signature or behavior rule matched.
External intel
Complete3 of 3 independent reference sources completed.
Behavior
Plain-English impact first, then the observed runtime evidence.
Runtime flight recorder
Capture complete- 1isolated sandbox run
- 19MITRE ATT&CK techniques
- 11spawned processes
- 0network contacts
- 40filesystem & mutex artifacts
Attack story
Runtime observations grouped by analysis stage. Arrows organize the stages; they do not claim chronology or causality.
Input file
The submitted object
- FileObserved
tb_grumblebum_2_7.dll
a9273bc1267bc431971e9cebdf2b6c9b26ade011145dbe296705ecd7a8d3f74d
01Uploaded file
Processes
Runtime execution
- ProcessObserved
Observed process
"C:\Windows\System32\rundll32.exe" "C:\Users\<USER>\Desktop\library.dll",#1
02Isolated runtime analysis - ProcessObserved
Observed process
C:\Windows\SysWOW64\WerFault.exe -u -p 8 -s 748
03Isolated runtime analysis - +1 more recorded observation in Analyst mode
Files
Created or changed
- Written fileObserved
Temp
C:\ProgramData\Microsoft\Windows\WER\Temp
04Isolated runtime analysis - Written fileObserved
0357c3fa-64a0-4008-87f1-d5a89ee2114f
C:\ProgramData\Microsoft\Windows\WER\Temp\0357c3fa-64a0-4008-87f1-d5a89ee2114f
05Isolated runtime analysis - +1 more recorded observation in Analyst mode
5 recorded facts from one runtime window. Every fact remains independently traceable in Analyst mode.
What this file did when executed
This file was detonated in 1 sandbox and its runtime behaviour was observed.
Adversary techniques mapped to the MITRE ATT&CK framework.
- C:\ProgramData\Microsoft\Windows\WER\Temp
- C:\ProgramData\Microsoft\Windows\WER\Temp\0357c3fa-64a0-4008-87f1-d5a89ee2114f
- C:\ProgramData\Microsoft\Windows\WER\ReportQueue
- C:\ProgramData\Microsoft\Windows\WER\Temp\cbd6214e-5607-4389-a36c-2bb76d8fbede
- C:\ProgramData\Microsoft\Windows\WER\ReportArchive
- C:\ProgramData\Microsoft\Windows\WER\Temp\WER4694.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WER4889.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WER49F2.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WER4694.tmp.dmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WER4889.tmp.WERInternalMetadata.xml
- Local\WERReportingForProcess8
- Global\AmiProviderMutex_InventoryApplicationFile
- Global\63b47a17-df60-4676-bf86-95a21dcd23c3
- \Sessions\1\BaseNamedObjects\Local\WERReportingForProcess7796
- \Sessions\1\BaseNamedObjects\Global\8901c014-dbef-4035-9e41-eadfec324298
Files this sample writes at runtime
This file drops 6 children at runtime. None are currently flagged malicious in our cache.
- 6235bdfc16771d573217…549785Never scannednever seen before
- 964eac20d1bad4bf9fed…f21eafNever scannednever seen before
- 0f22adb8c5237dcdfc69…348745Never scannednever seen before
- 4cde22dff8956aea8473…4c3eb2Never scannednever seen before
- 2c5854555762226c3250…2a8b4dNever scannednever seen before
- 91e0e31ded8364eb0a6e…278f07Never scannednever seen before
Detection & Forensics
Consensus, attribution, signatures, code structure, prevalence, and identity.
Evidence integrity
Chain of custody for the facts preserved in this report.
- 1rule hit recorded
- 1 / 75engines flagged
- 18sources in submission history
Why these facts are shown
Each statement identifies whether it was directly recorded or derived from saved scan facts.
- 01
1 high-confidence signature or behavior rule matched this file.
Verdict inputView chapterProvenanceDerivedSourceSignature and behavior rulesObserved at - 02
1 of 75 antivirus engines flagged the file, including Cynet.
Verdict inputView chapterProvenanceObservedSourceAntivirus analysisObserved at - 03
The hash has been submitted 22 times from 18 sources.
ProvenanceDerivedSourceSaved report factsObserved at - 04
Scanned file: tb_grumblebum_2_7.dll — a9273bc1267bc431971e9cebdf2b6c9b26ade011145dbe296705ecd7a8d3f74d
ProvenanceObservedSourceUploaded fileObserved at - 05
Observed process — "C:\Windows\System32\rundll32.exe" "C:\Users\<USER>\Desktop\library.dll",#1
ProvenanceObservedSourceIsolated runtime analysisObserved at - 06
Observed process — C:\Windows\SysWOW64\WerFault.exe -u -p 8 -s 748
ProvenanceObservedSourceIsolated runtime analysisObserved at - 07
File written: Temp — C:\ProgramData\Microsoft\Windows\WER\Temp
ProvenanceObservedSourceIsolated runtime analysisObserved at - 08
File written: 0357c3fa-64a0-4008-87f1-d5a89ee2114f — C:\ProgramData\Microsoft\Windows\WER\Temp\0357c3fa-64a0-4008-87f1-d5a89ee2114f
ProvenanceObservedSourceIsolated runtime analysisObserved at
Detection sources at a glance
The available sources did not agree on a named threat category.
MalwareBazaar, YARAify, and CIRCL hashlookup completed and returned no entries for this hash.
Signatures and behavior heuristics
A community signature or high-severity behavioral heuristic matched. Signatures identify known patterns; heuristics are strong leads but are not proof on their own.
The saved runtime evidence maps this activity to MITRE T1055 (Process Injection). The mapping supports possible process injection, but it does not prove the exact injection method or the operator's intent.
Evidence"C:\Windows\System32\rundll32.exe" "C:\Users\<USER>\Desktop\library.dll",#1
1 of 75 engines flagged this file
View all 75 engine results
Section entropy & packers
No high-entropy executable section or known packer signature was detected. Data and resource sections can still have high entropy without indicating packed code.
How widely this file has been seen
Moderate prevalence — neither rare nor common. No strong prior applies.
Fingerprint and provenance
- File name
- tb_grumblebum_2_7.dll
- Format
- Win32 DLL
- Code signing
- No verified publisher
- Size
- 2.1 MB
- Last analyzed
- Sep 5, 2026, 3:50 PM UTC
a9273bc1267bc431971e9cebdf2b6c9b26ade011145dbe296705ecd7a8d3f74dSafety & FAQ
Complete recovery guidance and answers for the next decision.
What to do now
This file appears low risk based on the evidence available now.
- Recovery step 01
Use it only as part of software obtained from the developer's official site or another source you independently trust.
- Recovery step 02
A clean result reduces known risk, but it cannot guarantee that every new or targeted threat has been detected.
- Recovery step 03
Keep your antivirus and Windows updates switched on so you stay protected.
Safety FAQ
Direct answers grounded in the saved verdict and evidence in this report.
Is tb_grumblebum_2_7.dll safe?
What is tb_grumblebum_2_7.dll?
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Community
Member reviews and reports for this exact file hash.