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

Static analysis result for SHA-256 0a749a4d07694d7c…

MALICIOUS

Office (OOXML) / .XLSM

42.4 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-01-20
MD5: 211628263eb9410a78f869226bd69718 SHA-1: 00e2d446f5d92b6de8bd0cf0e38ea6223ade167b SHA-256: 0a749a4d07694d7c6e27bb17cb0231037bafe4539f77a9c0d218c974e3eecb61
370 Risk Score

Malware Insights

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

The Workbook_Open macro executes a command that downloads a script from 'https://olugun.co.za/home/micors.scr' using certutil.exe and then executes the downloaded file. This indicates the document is a dropper designed to download and execute a second-stage payload. The presence of a Workbook_Open macro and the use of cmd.exe point to a common macro-based malware delivery technique.

Heuristics 10

  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • External hyperlinks (3) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 3 external hyperlinks — clickable URLs are stored as external relationships. First target: http://go.microsoft.com/fwlink/?LinkId=846285
  • 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 https://olugun.co.za/home/micors.scr
    • http://go.microsoft.com/fwlink/?LinkId=846285
    • http://go.microsoft.com/fwlink/?LinkId=844969

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
22fef8da14642c9b16b3f3ba05822938ead58166e0210fbca160531752c16299		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1395 bytes
vbaProject_00.bin
7d405b77d7e38c16335305e3896adf870da8505150de4def7f35fa00091ef487		 vba-project OOXML VBA project: xl/vbaProject.bin 6144 bytes
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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