Ursnif — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 6711d38e7e0c51ba…

MALICIOUS

Office (OOXML) / .XLSM

228.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 15.0300
MD5: 681f15c72a949c33e24251225274fb20 SHA-1: d94a200fe3c4493bef227624297c66f784783ab5 SHA-256: 6711d38e7e0c51ba7fb2b9341a8a10cf032c78f22fcdf19f643553b7ab796efa
282 Risk Score

Malware Insights

Ursnif · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The file is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. These macros utilize dangerous functions like CALL and EXEC, and the document body contains a string that appears to be a command to execute regsvr32 with a URL pointing to a DLL. This indicates the macro's purpose is to download and execute a second-stage payload, consistent with the Ursnif banking trojan family. The ClamAV detection also confirms its malicious nature.

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://premiumstati.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
35be3152477d5f3ae12405dd948cf1644101c79f2381d849d1ff13e27ae50dee		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1246767 bytes

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