Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 d1ff364cae233ccb…

MALICIOUS

Office (OOXML) / .XLSM

90.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-24
MD5: e95e7ea118f3078b16444f808fc698d6 SHA-1: f935c5d797609e0219ff57f88b1e41b4f817de6c SHA-256: d1ff364cae233ccb7ef06ea7581cfe3840ebd09c65a699d528c4489ce170a170
290 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1218.010 System Binary Proxy Execution: Regsvr32 T1059.005 Command and Scripting Interpreter: Visual Basic T1105 Ingress Tool Transfer

This malicious Excel document utilizes Excel 4.0 macros, a technique commonly associated with Emotet. The macros contain formulas that construct and execute a command using regsvr32.exe to download and run a payload from one of the embedded URLs. The critical heuristic 'OOXML_XLM_DANGEROUS_FN' confirms the use of dangerous XLM formula APIs for execution. The ClamAV detection also points to Emotet. The script's intent is to download and execute a second-stage payload from the embedded URLs.

Heuristics 7

  • 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.
  • 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.EmotetExcel02220-9940032-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.EmotetExcel02220-9940032-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 5 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://www.ajaxmatters.com/c7g8t/zbBYgukXYxzAF2hZc/
    • http://www.beholdpublications.com/home/BABxyyWZx8Vu/
    • http://explorationit.com/screwing/AxLm/
    • http://donboscoschoolputhuppally.org/wp-content/UuQ7LBsPoGu9Q/
    • http://myclassroomtime.com/mongery/ZlPsROtQiXIujmJmAA/
    • http://www.ajaxmatters.com/c7g8t/zbBYgukXYxzAF
    • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
fc9253ffcb683b17b2963a329e0d1078315a68ecc8af492238ff27be69741b1f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3613 bytes
xlm_sheet_01.xml
6922c877af9b5ffe857609a5d410eac153e8905bd35dfd19cf6ef8e3fb0636e6		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1204 bytes
xlm_sheet_02.xml
60579741b1b65a4181fd818a651bece32da461189f50a30098e233a7c5fed525		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1227 bytes

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