Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 f88fe02c1d4eeaf5…

MALICIOUS

Office (OLE) / .XLS

95.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-07-13
MD5: 3e513cafcaeaf93df03c2357f831d4e2 SHA-1: c5b09ee54eacf54d673f02adc777cd3b5b5551fa SHA-256: f88fe02c1d4eeaf522b088ab279cda70ba1a531f33fd4af6e5afa3c96c5b7b05
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro, a known technique for executing malicious code. ClamAV detection explicitly names this as Emotet, a downloader family. The macro uses dangerous functions like RUN, indicating it's designed to execute a secondary payload.

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-ea81817e7f807ab1-9952142-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-ea81817e7f807ab1-9952142-0
  • 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
168e7c20400a87ec53e7f85fc05780d92d7341ae7fdc256e3891ea4b48ec5adc
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8132 bytes