Emotet — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 17f76c53880aaba7…

MALICIOUS

Office (OOXML) / .XLSX

144.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 301c32bd6ab79522e1f1ce352b254cc3 SHA-1: 6bf4a2eaa1bd0919dc6e0a4ba17b19e76da114ff SHA-256: 17f76c53880aaba785039d45555ecb9e41c702a674837457d2ef74a98ce8de87
270 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel file containing multiple Excel 4.0 macro sheets, identified by critical heuristics. These macros utilize dangerous functions like FORMULA to download and execute payloads from several URLs. The ClamAV detection name 'Xls.Downloader.EmotetRed022215-9938912-0' strongly suggests the Emotet family. The script attempts to download a file from the reconstructed URL 'http://desayunosdesde.casa/wp-content/lyNShWgYN7F/' and execute it using 'rundll32.exe ..\dwd1.ocx'.

Heuristics 7

  • Excel 4.0 macro sheet (7 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: FORMULA critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • ClamAV: Xls.Downloader.EmotetRed022215-9938912-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetRed022215-9938912-0
  • External relationship medium OOXML_EXTERNAL_REL
    External target in xl/externalLinks/_rels/externalLink1.xml.rels: /Users/Admin/Desktop/File/4f/Сir-ZV/Cir/1.xlsm
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 9 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
845190ff95687dd3bed60f8155a4703d187c9ac3d57c95b5f1e5fbccfcda8bf1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3818 bytes
xlm_sheet_01.xml
17a44bab46f03e771bd6542298156e3f6d09e434efc242a62b869dfb808c8fe0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1339 bytes
xlm_sheet_02.xml
e0e53f2efa6401d85f42fc271b8a5f25f093236955ae9e2f8aff086ade287b72		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1334 bytes
xlm_sheet_03.xml
99c0021f265b2512c81119e70583856c3b88d92cfcf4088dd76957bd454698ca		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1337 bytes
xlm_sheet_04.xml
505da860283599ae30bb243e4b86ce81f7bcbf678c783ee47ffef058c21fdfa5		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1341 bytes
xlm_sheet_05.xml
33833c2bb127cd3da704c0fa39beca9ede4ef247ba80706d40a7c8cb5fdddbee		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet5.xml 1256 bytes
xlm_sheet_06.xml
9db93655cb6fd9e30bf1d3ffbd4e22d858cd95d48236de02bbc820699d35abf8		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet6.xml 1177 bytes

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