Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 cd157abb678f29ac…

MALICIOUS

Office (OOXML) / .XLSM

431.1 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-05-24
MD5: 2e447b66925feb09d8f55653dd9955f9 SHA-1: db7fcbb81d2bfbd0627aa6cbfc67dc27e4ce2469 SHA-256: cd157abb678f29acfb7d4461fbdb5005dee9bd33ed4ba07c186b63d1746547fe
382 Risk Score

Malware Insights

MITRE ATT&CK
T1059.003 Windows Command Shell T1204.002 Malicious File T1105 Ingress Tool Transfer T1059.005 Visual Basic

The Workbook_Open macro executes a command using cmd.exe to download a batch file from the URL "http://3.70.157.79/class/loader/uploads/MT02201573.bat" using certutil.exe and then executes the downloaded file. This indicates a downloader pattern designed to fetch and run a second-stage payload.

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://3.70.157.79/class/loader/uploads/MT02201573.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
24bfce9e4c358c2605d28571032f52980da0d5d2390e2b76f2436fb6d67db212		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1131 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
c1d9924a42d89dc7c7c4cf1ed1db4cb98d9a92919a28df7caa753ffe53c57d08		 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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