Office (OOXML) / .XLSX malware analysis — malicious · 197b3fbed541ad22

MALICIOUS

Office (OOXML) / .XLSX

315.8 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: 63be1b28e8eff44af5ef5dac9c0898f1 SHA-1: f54e3aee3e197f9cd3189af62c888caee3e4b6f7 SHA-256: 197b3fbed541ad22a0f7e2644a84ef7b9ecdeb747114473516b3b80728b80969

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 are known to be used for malicious purposes. The macros are likely designed to execute arbitrary commands, potentially downloading and executing a second-stage payload. Due to the truncated nature of the extracted macro content, specific commands or URLs could not be identified.

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` `b8a9324f37743ea8ca756aeff4c50c62a2bb5c433e13c6ef1c1a5f897ad89e10`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	321545 bytes

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