Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 f1dc179d7a3aeb57…

MALICIOUS

Office (OOXML) / .XLSX

1.13 MB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-05-25
MD5: 45cef37fd951322b7c6a15d17bff8c99 SHA-1: 4352bb627c47d998023aceb76ba94729fdf6a03b SHA-256: f1dc179d7a3aeb57b86d939b5b4d116b3b7778f9ac79b11d1c2e5a410436effa
120 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is identified as malicious by ClamAV with the signature Xls.Downloader.Qbot-b760f03262b6e23b-9950440-0. The embedded Excel 4.0 macros contain strings that reconstruct paths such as 'C:\Windows\System32\svchost.exe' and 'C:\Users\Public\Documents\svchost.exe', indicating a likely attempt to download and execute a second-stage payload, consistent with Qbot's behavior. The macro also contains functions like 'URLDownloadToFile' which further supports this. The presence of multiple macro sheets and the critical heuristic firing for OOXML_XLM_MACROSHEET confirm the use of Excel 4.0 macros for malicious purposes.

Heuristics 2

  • Excel 4.0 macro sheet (4 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.
  • ClamAV: Xls.Downloader.Qbot-b760f03262b6e23b-9950440-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot-b760f03262b6e23b-9950440-0

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
a537b74caa9aff2d58a5c283562e9193cbcee1ec1598a20149d3292fc4d5c8ec		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 2286 bytes
xlm_sheet_01.bin
ea5fcee142a9af13fb8eeb8f9fc87ad7791a0f0faa22efda136eabd54cf1631f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 1906 bytes
xlm_sheet_02.bin
0961a82d4316cbd6c555ae6dfc0dbbc481b52f45cbb53ea43fe3a0dc752cd34b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.bin 337 bytes
xlm_sheet_03.bin
f906ee3df91cbc1fd7e0b20c2278d8825b4db29c6770cef788049f6d22f94413		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.bin 1002 bytes

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