Emotet — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 4605ae07e63515a7…

MALICIOUS

Office (OOXML) / .XLSM

49.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-16
MD5: 08eb0a933b23adf7b31caab77fe8978a SHA-1: 0d1e100c57f19962f777d998d1bb791b3ac4d16e SHA-256: 4605ae07e63515a7e7f6e4e43feb71217e2c2b44044e414e792591d34ca437d3
250 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet (XLSM) that utilizes dangerous functions like FORMULA to download and execute a second-stage payload. The script concatenates multiple strings to form URLs, including 'https://ballpointmedia.com/css/WDvvKlTTncgkazP/', which is used to download 'regsver32.exe'. This behavior is characteristic of the Emotet family, which often uses macro-enabled documents for initial infection. The presence of hidden sheets and the use of Excel 4.0 macros further support this assessment.

Heuristics 6

  • 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.Emotet03221-9941792-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet03221-9941792-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 6 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
561bd2ad03d5ff349d3a0a4fbda71b956dd8d97a0dbce4e25549bf8a7721c5df
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 4049 bytes
xlm_sheet_01.xml
4f892349a6f0ce9450df5d764f02eea0a737d43225bc39e0b3e39eaafe266901
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1276 bytes
xlm_sheet_02.xml
f8dcec9dac216a8c4fc7140768d73598afe199c381abfb2f58ad13ed8f5733f6
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1152 bytes