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

Static analysis result for SHA-256 4f1f434ec2ea581f…

MALICIOUS

Office (OOXML) / .XLSM

27.3 KB Created: 2021-08-19 14:03:52 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-03-08
MD5: 3812dbaca86e598096ae22ccac543a57 SHA-1: 7f0bc7b9b05ce41219324f8a33c809b004bc0611 SHA-256: 4f1f434ec2ea581fcf871906d4d726674a54eeee441187b69b5534e65cb7287f
382 Risk Score

Malware Insights

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

The Workbook_Open macro executes a command using cmd.exe to download a batch file from the URL "http://13.112.233.199/share/RF50113025776.bat" and then executes it. This indicates the sample's primary purpose is to act as a downloader for further malicious payloads. The ClamAV detection of 'Xls.Dropper.EPPlus-9802867-2' further supports this assessment.

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://13.112.233.199/share/RF50113025776.bat

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
a78833eeff922697230cb0c5542410fc59b2d4eaff73d92adaddbc5684ee925e		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1128 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
24eadc0a252a4e1945a8da803f7467d35fcfa23a125664a7e0eb6f854eaf37f1		 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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