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

Static analysis result for SHA-256 65cea9811034ab82…

MALICIOUS

Office (OOXML) / .XLSX

1.17 MB Created: 2022-04-29 12:58:15 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-04-29
MD5: c4eeee3b55d2764c3b91a041b2f67b04 SHA-1: 4d58d7ee14bd02f9c83e2b864037dd0954efea60 SHA-256: 65cea9811034ab826cd29d81c9e89a7dd054869f45ef617e5e7f76c29ffc498c
120 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, identified by the OOXML_XLM_MACROSHEET heuristic. These macros appear to be designed to download and execute a second-stage payload. The script attempts to construct file paths such as 'C:\Terto\Vost\Yoonsa.oooooooooooooooooxxxxxxxx', suggesting a download or staging operation. The ClamAV detection further confirms the malicious nature of the file.

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.GreenOffice12210-9918618-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.GreenOffice12210-9918618-0

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
emf_00.emf
4f74df9f453f3ccfb865b44b4e8300dfae3c730acf04c6bb3f22c464f5b5ed6d		 ooxml-emf OOXML EMF part: xl/media/image2.emf 4487316 bytes
xlm_sheet_00.bin
1ba7ee19cf3bbd303bf1bd6e21378e719a80bf206e604760f064c6b26286925e		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 2653 bytes

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