Office (OOXML) / .XLSX malware analysis — malicious · f1d21cd76db645ac

MALICIOUS

Office (OOXML) / .XLSX

110.5 KB Created: 2021-09-08 10:16:58 UTC Authoring application: Microsoft Excel 12.0000

MD5: 58453775d0dbe884f907f3b58a117192 SHA-1: d5722c31b6c78fa89959854a0841693b0eb3b1b5 SHA-256: f1d21cd76db645acbeab2c52be8411b3b29b892a905263d7fc3991dabeadea93

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The file is an Excel spreadsheet containing embedded Excel 4.0 macros. The heuristics indicate the presence of these macros, which are often used to execute arbitrary commands or download additional payloads. No specific URLs or commands were extracted, limiting further analysis of the exact execution chain.

Heuristics 1

Excel 4.0 macro sheet (2 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `6218ec10386474a66b378c53580b3ad3ac84218dd12e21320c7fa461848ab05d`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	304 bytes
`xlm_sheet_01.bin` `859b68799e6e457532addec293f84b74ab2fed260b73df21089d654b14232929`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.bin	926 bytes

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