Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 00780ee32f979bea…

MALICIOUS

Office (OOXML) / .XLSX

21.4 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 4d98b03e9b13700121223b07b897e345 SHA-1: 8cbf0d82b93e7a60ab434277f6859c15b4a7e50d SHA-256: 00780ee32f979beafe9abdf3e37f84f9ccb4c763767efdda1c33bf52a50e3493
240 Risk Score

Malware Insights

Qbot · confidence 95%

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

This Excel file contains critical Excel 4.0 macros that leverage WinAPI functions like URLDownloadToFileA and ShellExecuteA. The macros are designed to reassemble a payload from CHAR() formulas, indicating an intent to download and execute a second-stage executable. The ClamAV detection name 'Xls.Dropper.QbotDocu12020-9818439-0' 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.
  • XLM payload reassembled from CHAR()/split formulas critical OOXML_XLM_REASSEMBLED_PAYLOAD
    An Excel 4.0 macro sheet builds its payload inside the formula token stream by concatenating per-character CHAR() calls and string fragments, so no WinAPI name, shell command, or URL is ever contiguous in the .bin for a literal-bytes scan to find. Reassembling the formulas recovered download/execute API names, LOLBin commands (regsvr32/rundll32/mshta/wmic/powershell), or a payload URL — the de-obfuscated download-and-run kill chain.
  • ClamAV: Xls.Dropper.QbotDocu12020-9818439-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.QbotDocu12020-9818439-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
3fd5d57a928c8ba818db7c001502d9473d992f17b434009561c9d63b9b02fe10
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 22574 bytes