Office (OOXML) / .XLSX malware analysis — malicious · 64ac8ed6270b51cb

MALICIOUS

Office (OOXML) / .XLSX

81.3 KB Created: 2021-02-26 07:53:41 UTC Authoring application: Microsoft Excel 16.0300

MD5: 2df081ec4f78d8a50c5e1e5620a734c5 SHA-1: b707f6c8eeb41cc23b08f9817c50803ec97ec75d SHA-256: 64ac8ed6270b51cb39ba4256f0cf2990401cd608c358e6edbc3e8402ad400270

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing Excel 4.0 macros, which is a known technique for executing malicious code. The macros are likely responsible for downloading and executing a second-stage payload. Due to the obfuscated nature of the extracted macro content, the exact execution path and final payload could not be determined.

Heuristics 1

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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `c4316f2f2550a9f3c3687372b05f7352d0ae432eafa000f6d2763a9e5daa9159`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	4569 bytes

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