Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 91310fe924a33b65…

MALICIOUS

Office (OLE) / .XLS

55.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-25
MD5: e042fb184dc21ea0d79ff774357aa587 SHA-1: bac1361f98880b313a51a75e534cbf41cd4fc112 SHA-256: 91310fe924a33b6548e38f47964809bb9d8e545a070e2863ddd536c080c5358b
262 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code. The macros reconstruct and attempt to download payloads from six different URLs. The ClamAV detection and the nature of the macro execution strongly indicate the Emotet family, a notorious downloader.

Heuristics 6

  • 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.
  • URL reconstructed from XLM cell array (6 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.Emotet03220-9942564-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Emotet03220-9942564-0
  • 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 https://www.clintmorey.com/wp-content/QSzbH8Ikl8E/
    • https://ciberfallas.com/wp-admin/4sU1dATy/
    • http://code786.com/beeldOLD/ATnNk316/
    • http://combatenterprises.com/cgi-bin/1BabmNqCKBxUIzUy/
    • http://sd-1684625-h00001.ferozo.net/PaginaMasVieja1321654/F1M5dBu8axuQkx0p8/
    • https://comarcahoy.com.ar/wp-content/S1nkrxCcDV89DLpTXhqC/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
09766ace40a05da85050d6e9ec7093d6722df7e33a81547c627ee8e0e9dbf1ff		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6951 bytes

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