Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 faa6646e0ca94c1c…

MALICIOUS

Office (OLE) / .XLS

126.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-29
MD5: 98011b43e7fb405ef804e56539a3382b SHA-1: 28857124287d927994496dadab7d446fac3994da SHA-256: faa6646e0ca94c1c5b41c2efaf4254b0e3864f26bcbe5b71763e99ec9fe18016
262 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1059.001 PowerShell: PowerShell T1204.002 Malicious Link: Malicious Link

The file contains Excel 4.0 macros with an Auto_Open entry, which is a critical finding. These macros are designed to execute dangerous functions, including downloading payloads from multiple URLs. The ClamAV detection explicitly names Emotet, and the reconstructed URLs are consistent with Emotet's typical distribution methods. The macro attempts to execute 'regsvr32.exe' with a DLL, indicating a download and execution chain.

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: Xls.Downloader.Emotet-adc2d23d2dc26dd0-9950240-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-adc2d23d2dc26dd0-9950240-0
  • 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://www.forensisbilisim.com/ankara/bplsmKfaKAwAyavNj/
    • https://www.faitmaison.uk/wp-admin/BZMoK/
    • http://www.parapetyrs.cz/wp-content/uploads/UTnG7GKKkZf/
    • http://www.fahriefe.com.tr/yargitaykararlari/aVg/
    • http://www.drcno.sk/_sub/FcEgwPugDI7wr2/
    • https://www.whow.fr/wp-includes/aZo78JmHBoEmW6fVQ/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
baa385ee141091e506d4fc8952e60f349e2a144300202c59dbc3e03ea3f9b493		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6541 bytes

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