Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 4213677263ce404c…

MALICIOUS

Office (OLE) / .XLS

115.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-02-24
MD5: f31e5625ae83477f06224e9f471ac87c SHA-1: cdaa852dd05fa0251289fadb317004cbeb7f8935 SHA-256: 4213677263ce404cc1aeaeb948d85eeb372c93d5a72b690f674bfbbc10dedb39
302 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1218.010 System Binary Proxy Execution: Regsvr32 T1059.005 Command and Scripting Interpreter: Visual Basic

The file contains Excel 4.0 macros with an Auto_Open entry, which is a known technique for executing malicious code. The macros reconstruct and execute URLs using regsvr32.exe, as indicated by the 'SE_LOLBIN_RUN_COMMAND' heuristic and the reconstructed command line in the DOC BODY. The ClamAV detection explicitly names this as Emotet. The primary intent appears to be downloading and executing a second-stage payload from the listed URLs.

Heuristics 7

  • 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: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-bd646319c2d29cd6-9951195-0
  • 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.
  • 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://new.tokosatu.com/wp-admin/QzzQZAIDuBhOplwOnhJ/
    • https://vasilestudio.com/wp-admin/vh8oEprCE3/
    • https://filmywap.casa/wp-includes/mSDKKyOs21N/
    • https://fullmaza.newsfresh.net/xc70-200k/lhXXF/
    • https://chughtai.xyz/cgi-bin/r0hNrJM20mGthgS8/
    • https://new.tokosatu.com/wp-admin/QzzQZAIDuBh

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
44868ec36ac596c7da257b2a57271a68a978068da03633e69756d991cbba1025		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6604 bytes

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