Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 75af70e23da2b599…

MALICIOUS

Office (OOXML) / .XLSX

167.3 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000
MD5: 88385d7c98280b9a188a499c47058b5a SHA-1: 48ae0de2a9fe51a577086b186f55e72bb3aab37f SHA-256: 75af70e23da2b599da4494660650ed0cf042caacd80749f3015b4cb323b57b8f
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The critical heuristic firing indicates the presence of an Excel 4.0 macro sheet. The embedded script within this sheet attempts to write a file named 'ToxjmwABviL.rtf' to the 'C:\ProgramData\' directory. This suggests the macro is likely a downloader for a second-stage payload.

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.

FilenameKindSourceSize
xlm_sheet_00.bin
784aaaf5fbb27557696f9deaf45e59d9bd739d7383b9856d0ecd7ee6688392dd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 1226 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.