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

Static analysis result for SHA-256 8f83d97afb25938e…

MALICIOUS

Office (OOXML) / .XLSM

102.2 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300
MD5: ffea56e394fd8237275d61385039302c SHA-1: cc36858a1b1159713e33886cc3c34c7dd74feaf6 SHA-256: 8f83d97afb25938e23097c6a3a79061c12c558b6a51e23878355034155c2f709
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 'http://18.159.59.253/derek/QyJEqOV5XDT3ygH.bat' using certutil.exe and then executes the downloaded file. This indicates a downloader or dropper functionality. The ClamAV detection 'Xls.Dropper.EPPlus-9802867-2' further supports this assessment.

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://18.159.59.253/derek/QyJEqOV5XDT3ygH.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
55aa094cf6f884c9e3951cb70ce82bf77dd42f7c8a6ab62e63b9a465e5c1df2a		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1129 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
fe4f685f826523215e8c37d46282e97ffd6a1be4b5de6baf06b9750ef50844bd		 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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