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

Static analysis result for SHA-256 8641ebbe5bfc1832…

MALICIOUS

Office (OOXML) / .XLSM

431.1 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-04-12
MD5: b06c4160cd95141072551e60d499b0d8 SHA-1: 4ce53562e661fe7dbbb4993d67d52cc379d56154 SHA-256: 8641ebbe5bfc1832c1e84e63223672b7ceb4eb958c35ef625ee7235f1140c596
342 Risk Score

Malware Insights

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

The sample is an XLSM file containing a Workbook_Open VBA macro. This macro executes a command using cmd.exe and certutil.exe to download a file from http://100.26.109.199/r-7/loader/uploads/7841200103541000img.exe and then execute it. This indicates the file acts as a downloader for a second-stage payload.

Heuristics 8

  • 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
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — 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://100.26.109.199/r-7/loader/uploads/7841200103541000img.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
649b763e2b6e7965e40631c2bec4770672e86627058627304324dea55fc93a28		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1129 bytes
vbaProject_00.bin
28ad46dd84f3c5640f228d5e16bf3ba88dd13858e4501743fc35f579c115116f		 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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