Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 7d6d55d1698244ff…

MALICIOUS

Office (OLE) / .XLSX

109.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 998c7e83585dc7fd5928499bab2ccc04 SHA-1: 0da67582c652bf757ebbb1c920c42f166ab48a04 SHA-256: 7d6d55d1698244ffb80566752ad25de335f5b77e8d346038c01e60cb8a164555
262 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File Execution: User Execution of Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open macro that utilizes dangerous functions like RUN. The macros reconstruct and attempt to download payloads from five distinct URLs. ClamAV detection further supports this as Emotet. The reconstructed URLs are the primary indicators of compromise.

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 (5 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.EmotetExcel02220-9938626-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetExcel02220-9938626-0
  • 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 http://arzulens.com/wp-includes/7gySgTg/
    • https://simplinteriors.com/wp-admin/B1e/
    • https://www.swaong.com/wp-admin/k9Db4Vjafnk/
    • http://68bets.site/b/bL2bq71qNY/
    • https://farocf.com/wp-admin/rX9FcCxf0Cf4bj/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
50aac6306d81f77d2140d85b020a980d4c24646f532e5d63efea2f839d07ed30		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6315 bytes

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