Office (OOXML) / .XLSM malware analysis — malicious · b4b5d93468c950c3

MALICIOUS

Office (OOXML) / .XLSM

431.1 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-04-20

MD5: 24b4b81a11e374604337131b6e909492 SHA-1: 94591441038c840ebab0e427c562d3beeb6114ef SHA-256: b4b5d93468c950c37f210b9b14cb5c546a1f48389e8540cbad50d904bfcf8450

382 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File T1059.003 Windows Command Shell

The Workbook_Open macro executes a command using cmd.exe to download a batch file from the embedded URL using certutil.exe and then executes the downloaded file. The downloaded batch file is named 'Ofsiuud.exe.exe'. This indicates a downloader or dropper functionality.

Heuristics 9

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
LOLBin reference in VBA critical OLE_VBA_LOLBIN

LOLBin reference in VBA
ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
Workbook_Open macro high OLE_VBA_WBOPEN

Workbook_Open macro
cmd.exe reference in VBA high OLE_VBA_CMD

cmd.exe reference in VBA
Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://3.70.247.229/class/loader/uploads/TQL507852000.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `f447af45b8efff12e1083d8b247655b0a7406253ba971ace8e0372925dc8b101`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	1106 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.
`vbaProject_00.bin` `78a912a005de35e83b84600e23248f7553e1f116372ef93d2fbdfd6103ca2b40`	vba-project	OOXML VBA project: xl/vbaProject.bin	5632 bytes
Detection ClamAV: Xls.Dropper.EPPlus-9802867-2 Obfuscation or payload: unlikely

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