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

Static analysis result for SHA-256 02ddb087cb013274…

MALICIOUS

Office (OOXML) / .XLSX

140.7 KB Created: 2021-09-20 10:27:09 UTC Authoring application: Microsoft Excel 12.0000
MD5: 1de58af3ccf2846546ecf9e2183a33bd SHA-1: d9e17ec6ff45e2c9bf103d38fb1ce4caad05a84c SHA-256: 02ddb087cb013274cceb4ab72a7dc978553ec77ae472dd6244dece781719455c
120 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 macros, which are known to be used for malicious purposes. The heuristic firings and ClamAV detection strongly indicate that this file is a downloader for a secondary payload. The specific macro commands are obfuscated, but the overall intent is to execute arbitrary code.

Heuristics 2

  • 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.
  • ClamAV: Xls.Downloader.Trojan-a0425f7f2000faff-a0425f7f2000faff-9950268-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Trojan-a0425f7f2000faff-a0425f7f2000faff-9950268-0

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
4ba29628b3f7755417bc6df79127afca738ede30222d12113db364203b0830dd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 883 bytes

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