Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 2107fac26923df70…

MALICIOUS

Office (OOXML) / .XLSX

117.4 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-03-15
MD5: fc9fdd31ade48d8c64898d39ba5b8208 SHA-1: a0e7bd87ab2d973b938c8847ff8e9a5f0a08ee66 SHA-256: 2107fac26923df70eec2a6ee4a6d567e6523c5fe9775002f31e721656dbf15b7
180 Risk Score

Malware Insights

Qbot · confidence 95%

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

The file is an Excel document containing multiple Excel 4.0 macro sheets, as indicated by the OOXML_XLM_MACROSHEET and OOXML_XLSB_INTL_MACROSHEET_IN_XLSX heuristics. The ClamAV detection of 'Xls.Downloader.Qbot03220-9942292-0' strongly suggests a Qbot family downloader. The extracted macro content, though partially obfuscated, contains strings like 'FileA', 'UrlMon', and 'URLDownloadToFileA', indicating the script's intent to download a second-stage payload from a URL. The presence of multiple macro sheets and the downloader functionality are characteristic of Qbot's initial infection vector.

Heuristics 3

  • Excel 4.0 macro sheet (12 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • XLSB international XLM macro sheet hidden in .xlsx critical OOXML_XLSB_INTL_MACROSHEET_IN_XLSX
    OOXML package is named .xlsx but contains XLSB workbook parts and an international Excel 4.0 macro sheet. This hides XLM macro execution from scanners that trust the extension or only inspect XML worksheet parts. The technique is macro execution, not a document-parser CVE.
  • ClamAV: Xls.Downloader.Qbot03220-9942292-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot03220-9942292-0

Extracted artifacts 12

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
634354893576e307c65963ccace2b5e550032ed9362f8efca52602ab270a7938
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 1050 bytes
xlm_sheet_01.bin
5afafbf01f08461397defa63bddc057b80b257780a9236e908668beef68f4485
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.bin 482 bytes
xlm_sheet_02.bin
fd19c0386da3dd3c08345905679f48c054af85a8c94bed856e5388108422e105
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 2794 bytes
xlm_sheet_03.bin
0f6789a977a92c7b99385e78ab87d328344846dfcaa460b7d90345e138932489
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.bin 1196 bytes
xlm_sheet_04.bin
7d812db0fce9902a3d5229cfdfe5e8f22699c483faafb50592c6e9ddb517bbc3
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.bin 482 bytes
xlm_sheet_05.bin
b4ccc708800dd8bc23c880b7a894acc3eafef87cb2ef9efff43fd418c785af46
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.bin 482 bytes
xlm_sheet_06.bin
b662f6052e8802add465b0c459997e7886ea4cbcf0a375167ae9946a8090728d
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.bin 482 bytes
xlm_sheet_07.bin
9d6b5d56174dc4eccbf897c65266832e8509b95cba25cc17d95701bffb300077
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.bin 562 bytes
xlm_sheet_08.bin
23c41dfad63fdcb812ba78a635dc1b8d3e5f556453cc45372f922931a01c41d4
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet8.bin 442 bytes
xlm_sheet_09.bin
7547fa8e29fe1ff3ba5b446f2dabd0d80da1227f2aeb5a8c745081369650305a
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet6.bin 442 bytes
xlm_sheet_10.bin
b12d5ed97fc7186c5b4baa331f7146f12375d285939841c26f4e9d0d4765a6ad
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 783 bytes
xlm_sheet_11.bin
76289228588761679b2089219bfc2e48fe1593db5f0128b8b0dd690d39386a9a
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet7.bin 393 bytes