Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 dc65ca5509e81b2c…

MALICIOUS

Office (OLE) / .XLSX

76.0 KB Created: 2022-01-26 21:52:19 Authoring application: Microsoft Excel
MD5: f9e3e3d66423e49211cae930a2a5d890 SHA-1: 330d26438631b90ea0c5622780f03b70a90cab2d SHA-256: dc65ca5509e81b2cd73b1070ba5105ed08da693f485969121a66c658c544d2ca
322 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1566.001 Spearphishing Attachment T1059.003 Windows Command Shell

The file contains an Excel 4.0 macro sheet with an Auto_Open entry, which is a known technique for executing malicious code. The macro sheet references dangerous functions and includes a command to execute mshta with a URL, indicating it's designed to download and run a second-stage payload. ClamAV detection further supports its malicious nature, identifying it as a downloader.

Heuristics 8

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • ClamAV: Doc.Downloader.EmotetRed02220-9938633-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9938633-0
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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://91.240.118.168/zzx/ccv/fe.htmlB
    • http://91.240.118.168/zzx/ccv/fe.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
ae04d5c104f21141f430aad243ecbad709822bd8efcfd8c6a83945c0ae8dd42a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3673 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s). Carved macro source contains an auto-exec entry point and execution/download terms.