Ursnif — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 0b9dbde81e0d90e6…

MALICIOUS

Office (OOXML) / .XLSM

254.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 15.0300
MD5: 269f0ab1cbd9e86f0ed70368865179b7 SHA-1: e98d48841ab67d1a91b5918ddd1ac6b6f1731264 SHA-256: 0b9dbde81e0d90e69bc8fe04d3d06d31ad325665eb4d42c94d6e0a1ef6c49dd8
282 Risk Score

Malware Insights

Ursnif · confidence 95%

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

The sample is an XLSM file containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous functions like CALL and EXEC to download a DLL payload from 'http://premiumstatics.co/con3cti0n.dll' and execute it using 'regsvr32 C:\Progr amDa ocx ta\activX'. This behavior is consistent with the Ursnif banking trojan family, which often uses macro-enabled documents to deliver its payload.

Heuristics 6

  • Excel 4.0 macro sheet (1 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: RUN, CALL, EXEC, HALT 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: Doc.Dropper.UrsnifIT1220-9803735-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.UrsnifIT1220-9803735-0
  • 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.
  • 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://premiumstatics.co/con3cti0n.dll
    • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
1d63f29a38403dbf797904d94beb5099c8dc175bac6e9685454872254fa637b5		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1538757 bytes

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