Qbot — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 f45ed633c5efa0a4…

MALICIOUS

Office (OOXML) / .XLSM

150.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 9d1c3e8cfdd81e91f7038f99f00e972c SHA-1: 51c2e65e5da781aef07817001c72a60b8e5b9d14 SHA-256: f45ed633c5efa0a43378c2414dfc19e6849971061d121bf05dd106faf619a74d
250 Risk Score

Malware Insights

Qbot · confidence 90%

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic for Applications T1105 Ingress Tool Transfer T1059.001 Command and Scripting Interpreter: PowerShell T1120 Application Layer Protocol: Web Protocol

The sample contains Excel 4.0 macro sheets with an Auto_Open trigger and uses dangerous Win32 API calls via REGISTER and EXEC. The script in xlm_sheet_00.xml explicitly downloads a file named 'Kro.fis' from http://185.240.103.219/ and the script in xlm_sheet_01.xml executes the payload. This behavior is directly attributed to the Qbot family by the ClamAV detection signature.

Heuristics 6

  • Excel 4.0 macro sheet (2 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: REGISTER, RUN, 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: Xls.Downloader.Qbot06210-9875009-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot06210-9875009-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 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://185.240.103.219/
    • http://190.14.37.3/
    • http://185.183.99.120/
    • http://schemas.openxmlformats.org/spreadsheetml/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://www.iec.ch
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://ns.adobe.com/photoshop/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
c2e527cd52b125c07092c59d33090fc3ad9446b4f94b7ce503dfd27afbab14e6		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 2446 bytes
xlm_sheet_01.xml
38e9b51fd3cb35b28d5fe40b15ffb8f20ea947b6b435c697e9aa5042231a0b8a		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1747 bytes

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