Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 f5888c38941b009b…

MALICIOUS

Office (OLE) / .XLS

78.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-13
MD5: bf48aac213c1ff77d3de10530dbaf80d SHA-1: 48074f966b45226d373368819e81c7046c647935 SHA-256: f5888c38941b009b9302890c86032eac3391483d0fc8ba63927141400d587a24
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions, specifically the RUN function. The macro attempts to construct and download a payload from multiple URLs, including 'http://immobilgolfo.it/cgi-bin/Uf/'. This behavior is consistent with Emotet's typical delivery mechanism, which often involves macro-based documents acting as downloaders for further stages.

Heuristics 4

  • 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: Xls.Downloader.Emotet-add2d22d2bc26dd0-9950243-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-add2d22d2bc26dd0-9950243-0
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
214b0200160a0a56c6b45537e99f08bf5e131e2710192ec67ed6ddfaa9428b75		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6825 bytes

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