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

Static analysis result for SHA-256 aa01a0fe7d9562e5…

MALICIOUS

Office (OOXML) / .XLSM

42.4 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-16
MD5: 2c7e95a6377a8b172da2379e8df627de SHA-1: 61a5416984e01d6565ec5c41b094e0061e61deab SHA-256: aa01a0fe7d9562e50294848cce1c00652d609256255e7b8fec362e99ba1767b3
410 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 sample is an XLSM file containing a Workbook_Open macro that executes a command using cmd.exe. This command uses certutil.exe to download and execute a file from the URL "http://keepwealt.co.za/reparations/COMPLETE.pif". The macro's intent is to download and execute a second-stage payload, which is a common technique for malware droppers. The document body itself contains a lure to enable content, further supporting this malicious intent.

Heuristics 11

  • 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
  • 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 http://keepwealt.co.za/reparations/COMPLETE.pif
    • 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
25f336da7bab338af18b6aae7090c5dc47d69f007b98c967fbe40a2d24dfcabe		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1402 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
1d0a9307e1c06e414cd1f0987d2fb803a208afeff18a7950142306594cfcc447		 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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