Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 042a16b8333f8670…

MALICIOUS

Office (OOXML) / .XLSX

238.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-15
MD5: b6fab2820571181c390af87ae02b027e SHA-1: 0aa5f77948979e666341d61a35ad085228d35025 SHA-256: 042a16b8333f8670f71e220b7ee514c10874d1f310b547a051b7e08582f013f3
120 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file is an Excel XLSX document containing Excel 4.0 macro sheets, which are known to be used for malicious purposes. The ClamAV detection explicitly names Emotet, a known downloader family. The macros are likely responsible for downloading and executing a secondary payload, consistent with Emotet's behavior.

Heuristics 2

  • Excel 4.0 macro sheet (3 sheet(s)) critical OOXML_XLM_MACROSHEET
    Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • ClamAV: Xls.Downloader.Emotet-OOXML_XL-af43432fbcb8603c-9980048-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-OOXML_XL-af43432fbcb8603c-9980048-0

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
2eee5ae961fe5d65f35cf8570602a23d6ff455536901fc8d2a2296dc48ce0fed		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 2127 bytes
xlm_sheet_01.bin
76bb729a3fef1962dba3c4d4608bc67767a415d3068cfaefbab6dc04307f5716		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 428 bytes
xlm_sheet_02.bin
e107436a5f0bb0a25f454c2c3756c9b0d1befa58088a66751c1bc69dc47f10ec		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 428 bytes

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