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

Static analysis result for SHA-256 77dbaf0b290f261d…

MALICIOUS

Office (OOXML) / .XLSM

42.4 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-12-17
MD5: a4ff907fd616493dff151c1785ace60b SHA-1: 9c0508b168ac2ea8361cc6a1057e041e3219bb2d SHA-256: 77dbaf0b290f261d243e7413ed274bea43c68d588b14eeda7bb3e23efae9ff8f
370 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1140 Deobfuscate or Obfuscate T1059.003 Windows Command Shell

The Workbook_Open macro executes a command that uses certutil to download and execute a file from the URL https://aer-conditionat-romania.ro/a/a.exe. This is a common technique for delivering second-stage malware. The document body contains a lure to enable content, further supporting this malicious intent.

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://aer-conditionat-romania.ro/a/a.exe
    • 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
6e2aaa5a5a5133b21ee12aa9937a2772c3c302695815397e253b208e73b826e2		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1415 bytes
vbaProject_00.bin
c6710ff67eac7bc5094196afe09f768486a82da5764a670687b81c66ccd4eaba		 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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