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

Static analysis result for SHA-256 a2166861629c8fb5…

MALICIOUS

Office (OOXML) / .XLSM

102.2 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300
MD5: 3d26a2e4f3dccc9056b9718ae6a331f7 SHA-1: 5d58133a8417dd4bc518c6f98b566c710fd177cc SHA-256: a2166861629c8fb5e41417a35f29cc70a49dd58f0daf4e3d1e327b050c6ae0d1
382 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1059.003 Windows Command Shell

The sample is an XLSM file containing a Workbook_Open macro that executes a command using cmd.exe. This command leverages certutil.exe to download a batch file from 'http://18.159.59.253/cut/615472927758389.bat' and then executes it. This indicates a downloader or dropper functionality, aiming to fetch and run a second-stage payload. ClamAV detection further confirms its malicious nature.

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/cut/615472927758389.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
1c8fac47837417cb4561914d1ea5aa0eb4c1dddcbb327ef99c31abde6c65b3cc		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1119 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
417b9120eed3a379a7096dbf31bb05431943a2fb91ed09a728d0413961d6c737		 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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