Qbot Office (OOXML) / .XLSX malware analysis — malicious · 9ab9d22c6aa21839

MALICIOUS

Office (OOXML) / .XLSX

1.02 MB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-05-13

MD5: f6240ebe7ae11042841d1e95cd58c049 SHA-1: 1322c83d3761ea134d10d2676874dc4af4a3e5ad SHA-256: 9ab9d22c6aa218391415d1df98077212b67c5d82b150a813ba99b489abe3d2c0

180 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 that leverage the URLDownloadToFileA WinAPI function to download a file. The script then attempts to execute the downloaded file using regsvr32. The ClamAV detection name 'Xls.Downloader.Qbot-b760f03263b7c21b-9950248-0' strongly suggests the Qbot family. The downloaded file is likely a second-stage payload, and the execution via regsvr32 is a common technique for Qbot. The reconstructed URLs and file paths are included as IOCs.

Heuristics 3

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.Qbot-b760f03263b7c21b-9950248-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Qbot-b760f03263b7c21b-9950248-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `f758c93ce7d0c1deff19826bef37e51afbe225a006410e8b1544c7f941e68058`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	2282 bytes

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