Office (OOXML) / .XLSX malware analysis — malicious · 5dab399585f039fd

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: bcfd19cc77132ab08255966b4e261297 SHA-1: 10164288b9bf405350657a5ab7659d474a4ce229 SHA-256: 5dab399585f039fdc320b57420fb1aec967a5a21f95bb6c820dea687cddc0e1b

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. These macros are often used to download and execute further malicious payloads or to perform other harmful actions on the victim's system. The specific commands executed by the macros could not be fully determined due to truncation in the provided evidence.

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` `d06f4a8ef620f45807651646ef71318d44137155498ca4abb981c2dc3dd8137c`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	649934 bytes

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