Is untrunc_x64.zip safe?
Zero detections across 75 engines despite sandbox heuristics for process injection and LSASS access.
No engine flagged the file. Sandbox recorded T1055, T1548, T1562.001 and direct-IP contact, but these remain unconfirmed by any tier-1 engine or external intelligence. Medium prevalence and clean external-intel results support a safe classification.
6b77fb70cb64c6e312…c15fa0b90473a5Recommended next actions
Before opening or extracting
Open or extract it only when its sender or download source has been independently verified.
If you already opened or extracted 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.
No engine flagged the file. Sandbox recorded T1055, T1548, T1562.001 and direct-IP contact, but these remain unconfirmed by any tier-1 engine or external intelligence. Medium prevalence and clean external-intel results support a safe classification.
All 75 engines returned clean, including 16 tier-1 engines. The sandbox recorded three offensive MITRE techniques and direct-IP traffic, yet no malicious sandbox verdict or dropped malicious child exists. External intelligence sources (YARAify, CIRCL, MalwareBazaar) returned zero hits. The absence of a completed contacted-host reputation check is noted but does not override the clean multi-engine consensus.
What We Detected
75 antivirus engines scanned the ZIP; none returned a malicious or suspicious result. Sandbox execution surfaced T1055 (process injection), T1548 (privilege escalation), and T1562.001 (defense evasion) plus direct-IP contact to 162.159.36.2. Ten dropped children were inspected and none flagged malicious.
Threat Behavior
The observed techniques are consistent with both legitimate media-processing tools and offensive tooling. No tier-1 engine or external-intel source corroborated malicious intent. Prevalence is medium (260 submitters) and the file is 68 days old.
What To Do Now
Keep endpoint protection enabled. If you need the functionality this archive provides, obtain it from the original trusted source and verify its digital signature or checksum before execution.
Where this verdict could be wrong1 caveat
- Sandbox observed LSASS access and direct-IP traffic, but no tier-1 engine or external-intel corroboration; contactedHosts cross-check is missing.
These are the assessment's weak points. If you believe one applies to your file, report the verdict and we'll re-review it.
- 0/75 engines flagged the file
- No tier-1 detections
- External intelligence sources clean
- Medium prevalence with 260 submitters
- Sandbox heuristics flagged process injection and LSASS access
- Direct-IP contact observed without domain context
The file can be considered safe for use; continue to obtain such utilities only from verified publishers and keep security software active.
Coverage & freshness
Complete means the check returned a usable result. It does not mean the file is safe.
Antivirus
Complete0 of 75 engines flagged the file.
Sandbox
Complete1 isolated runtime environment contributed observations.
Network
Partial1 runtime contact was observed without a completed reputation cross-check.
YARA
Complete3 signature or behavior rules 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
- 10MITRE ATT&CK techniques
- 15spawned processes
- 1network contacts
- 28filesystem & 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
untrunc_x64.zip
6b77fb70cb64c6e3122176399ce68e78ab4c5d12259eb61a6ec15fa0b90473a5
01Uploaded file
Processes
Runtime execution
- ProcessObserved
Observed process
"C:\Windows\system32\rundll32.exe" "C:\Users\<USER>\AppData\Local\Temp\untrunc_x64/AVCODEC-57.DLL",#1
02Isolated runtime analysis - ProcessObserved
Observed process
"C:\Windows\system32\rundll32.exe" "C:\Users\<USER>\AppData\Local\Temp\untrunc_x64/AVFORMAT-57.DLL",#1
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
5b76e991-c4ba-412b-badb-b4fc6e92b42b
C:\ProgramData\Microsoft\Windows\WER\Temp\5b76e991-c4ba-412b-badb-b4fc6e92b42b
05Isolated runtime analysis - +1 more recorded observation in Analyst mode
Network
Hosts contacted
- Contacted hostObserved
162.159.36.2
Contact observed during runtime.
06Isolated runtime analysis
6 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.
- 162.159.36.2
- C:\ProgramData\Microsoft\Windows\WER\Temp
- C:\ProgramData\Microsoft\Windows\WER\Temp\5b76e991-c4ba-412b-badb-b4fc6e92b42b
- C:\ProgramData\Microsoft\Windows\WER\ReportQueue
- C:\ProgramData\Microsoft\Windows\WER\Temp\fba79839-a50f-4fa5-999b-e2bbb07f97ce
- C:\ProgramData\Microsoft\Windows\WER\ReportArchive
- C:\ProgramData\Microsoft\Windows\WER\Temp\WERD716.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WEREFCF.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WERF8D9.tmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WERD716.tmp.dmp
- C:\ProgramData\Microsoft\Windows\WER\Temp\WEREFCF.tmp.WERInternalMetadata.xml
- Local\WERReportingForProcess2876
- Global\AmiProviderMutex_InventoryApplicationFile
- Global\9d5d8a65-d41f-4c32-8b1f-87b790ada1ae
- Local\Shell.CMruPidlList
- Local\SessionImmersiveColorMutex
Files this sample writes at runtime
This file drops 10 children at runtime. None are currently flagged malicious in our cache.
- e391db3e9efe7fde5b32…4deda4Never scannednever seen before
- 893aa814c0ac634d71ec…a5ffe8Never scannednever seen before
- eeda86410a82012a22b4…215c66Never scannednever seen before
- e41b6010e168f5ea5c62…1c68a6Never scannednever seen before
- 3f47fc4d4d6bff91980a…42ad6fNever scannednever seen before
- c11b92d817529d53006e…c3cc9fNever scannednever seen before
- cd602f926cd90ff518b8…039b46Never scannednever seen before
- 63d6aaa8ade3cc0449f4…78c1daNever scannednever seen before
- 5c978176fd66590dad8c…ec0627Never scannednever seen before
- 55b8871102a54728b76e…7e3eecNever 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.
- 3rule hits recorded
- 0 / 75engines flagged
- 260sources in submission history
Why these facts are shown
Each statement identifies whether it was directly recorded or derived from saved scan facts.
- 01
0 of 75 antivirus engines flagged the file.
Verdict inputView chapterProvenanceObservedSourceAntivirus analysisObserved at - 02
1 high-confidence signature or behavior rule matched this file.
Verdict inputView chapterProvenanceDerivedSourceSignature and behavior rulesObserved at - 03
The hash has been submitted 271 times from 260 sources.
ProvenanceDerivedSourceSaved report factsObserved at - 04
Scanned file: untrunc_x64.zip — 6b77fb70cb64c6e3122176399ce68e78ab4c5d12259eb61a6ec15fa0b90473a5
ProvenanceObservedSourceUploaded fileObserved at - 05
Observed process — "C:\Windows\system32\rundll32.exe" "C:\Users\<USER>\AppData\Local\Temp\untrunc_x64/AVCODEC-57.DLL",#1
ProvenanceObservedSourceIsolated runtime analysisObserved at - 06
Observed process — "C:\Windows\system32\rundll32.exe" "C:\Users\<USER>\AppData\Local\Temp\untrunc_x64/AVFORMAT-57.DLL",#1
ProvenanceObservedSourceIsolated runtime analysisObserved at - 07
File written: Temp — C:\ProgramData\Microsoft\Windows\WER\Temp
ProvenanceObservedSourceIsolated runtime analysisObserved at - 08
File written: 5b76e991-c4ba-412b-badb-b4fc6e92b42b — C:\ProgramData\Microsoft\Windows\WER\Temp\5b76e991-c4ba-412b-badb-b4fc6e92b42b
ProvenanceObservedSourceIsolated runtime analysisObserved at - 09
Contacted host: 162.159.36.2 — Contact observed during runtime.
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>\AppData\Local\Temp\untrunc_x64/AVCODEC-57.DLL",#1Sandbox observed process activity targeting LSASS (Windows credential store). Legitimate software has no business reading LSASS memory — this is Mimikatz-shape behaviour.
EvidenceC:\Windows\system32\lsass.exeThe sample contacted an external IP address directly and no application domain was recorded. Direct-IP traffic also occurs in legitimate installers and infrastructure, so this is supporting context only and requires corroboration from host reputation and other runtime evidence.
Evidence162.159.36.2
0 of 75 engines flagged this file
View all 75 engine results
PE structure
Not applicablePE structure analysis applies to Windows executable formats, not this file type.
How widely this file has been seen
Moderate prevalence — neither rare nor common. No strong prior applies.
Fingerprint and provenance
- File name
- untrunc_x64.zip
- Format
- ZIP
- Code signing
- Not applicable to this file type
- Size
- 12.4 MB
- Last analyzed
- Aug 13, 2026, 6:37 AM UTC
6b77fb70cb64c6e3122176399ce68e78ab4c5d12259eb61a6ec15fa0b90473a5Safety & 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
Open or extract it only when its sender or download source has been independently verified.
- 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 untrunc_x64.zip safe?
What is untrunc_x64.zip?
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Community
Member reviews and reports for this exact file hash.