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

Static analysis result for SHA-256 3c17ab1dbaf497c3…

MALICIOUS

Office (OOXML) / .XLSX

94.8 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000
MD5: 6f7474923f6a3a643359d6165094cb14 SHA-1: bde580e303d22cdf1f7382540d72239a6e8551b9 SHA-256: 3c17ab1dbaf497c3de91338dddcdb72a59dd8b1cc7ab6907c60f83dbf9d8defe
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file is an Excel 4.0 macro sheet, as indicated by the OOXML_XLM_MACROSHEET heuristic. The embedded macro sheet contains obfuscated commands that appear to construct a path for a second-stage payload, likely C:\ProgramData\fjkgdjkngfdg\fjkgdjkngfdg. The macro's intent is to download and execute this payload, but the full execution chain is truncated.

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
3aa9277cd52512d58e896109b74c5d014486823a817013e249d7bbe0936976a8		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 3456 bytes

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