Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 6f47e0813821532c…

MALICIOUS

Office (OOXML) / .XLSX

21.4 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: c7afb329849b7eb55e5ff9e0c763834f SHA-1: 26e617134c636a6edaa82faf98c21763b1589ec0 SHA-256: 6f47e0813821532c8ec3c078312d56c4b11d3d56d6c97949dbb82bb66fe86d28
240 Risk Score

Malware Insights

Qbot · confidence 95%

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

The file contains Excel 4.0 macros, identified by critical heuristics, which are known to be used for malicious purposes. These macros leverage WinAPI functions like URLDownloadToFileA and ShellExecuteA to download and execute a secondary payload, as indicated by the 'Xls.Dropper.QbotDocu12020-9818439-0' ClamAV detection name. The reassembled payload strings suggest the download and execution of a file, likely establishing the initial foothold for the Qbot malware.

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

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