Office (OOXML) / .XLSX malware analysis — malicious · 240b001a08e5659d

MALICIOUS

Office (OOXML) / .XLSX

264.5 KB Created: 2021-06-18 16:09:13 UTC Authoring application: Microsoft Excel 16.0300

MD5: a2491f60c2869f38faaff67e38f1cd52 SHA-1: 20ea09516d97114c711065643c8645c741139398 SHA-256: 240b001a08e5659dff71de78549486c815e99c5d8b3fdfc32b45b46288aee33b

120 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The file is an Excel spreadsheet containing Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' heuristic. The VBA code includes a 'CreateObject' call, suggesting dynamic execution capabilities. The Excel 4.0 macro sheet, while truncated, likely contains commands to execute arbitrary code, a common technique for downloading and running further malicious payloads. The presence of both VBA and XLM macros points to a multi-stage attack vector.

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.
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
VBA project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `30fb8fee99175d290080d8a0fac253fde45640fd92380e068ac5bfb0025baabd`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	683 bytes
`vbaProject_00.bin` `01e8cb91f2444cf5c6680a86f4a478048dc0ad41d1a62d4a1b166a4d6fe6afd8`	vba-project	OOXML VBA project: xl/vbaProject.bin	12288 bytes
`xlm_sheet_00.bin` `814f58e6f20984bcaee5bbd4af5b00b077c6adf79ed6c39a00b6506db723e1e6`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	2548 bytes

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