Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 f8101de59e8b7992…

MALICIOUS

Office (OOXML) / .XLSX

1.18 MB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-04-20
MD5: 6a4199fdc52a75f082b799f2c883aa9d SHA-1: 687a3000aef48074e2d7a64b29b52dde51712271 SHA-256: f8101de59e8b79928840437c8e4b4c44113361b98831d92f8f9e3fb50433e94d
200 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1059.001 PowerShell T1218.011 Signed Binary Proxy Execution: Regsvr32

The sample contains Excel 4.0 macros that utilize WinAPI functions like CreateDirectoryA. The script attempts to create directories and write files such as 'C:\Flopers\Gorl\Vertu.OCX'. It also uses 'regsvr32' to execute a local file, likely a downloaded payload. The ClamAV signature 'Xls.Downloader.Qbot04223-9946522-0' strongly suggests the Qbot family.

Heuristics 4

  • 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • ClamAV: Xls.Downloader.Qbot04223-9946522-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot04223-9946522-0
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
24683ff192d5ff2bf2f841df675e1bec8a46ae42de534fcdbc64fb77dd4f33a5		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 4465152 bytes
emf_00.emf
481999fdbcc1fde5a4e3a4e9970e4bbf3c8dbeb2e2a366cc840aa848993159f4		 ooxml-emf OOXML EMF part: xl/media/image2.emf 2159428 bytes
xlm_sheet_00.bin
8084bcc5819ffecbcd0ce22ff3e5d2aef49eee72a09be45c6778f2ece968e04b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 2501 bytes

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