Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c27c99ccf59a3253…

MALICIOUS

Office (OOXML)

25.1 KB Created: 2021-03-11 12:01:54 UTC Authoring application: Microsoft Excel 16.0300
MD5: dddad3baf222908737a7f2ae85bc2e54 SHA-1: 8f22cdcf5d9176c6c3a4648dab5269d9f1ce7985 SHA-256: c27c99ccf59a325357f8f4bf50fbe03e3c5b2a08633689c7876d266aebd67764
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel file containing Excel 4.0 macros, indicated by the 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_DANGEROUS_FN' heuristics. The 'Auto_Open' defined name suggests automatic execution upon opening. The document body's prompt to 'Enable Editing' and 'Enable Content' further supports the malicious intent of executing these macros, which are capable of downloading and executing payloads.

Heuristics 4

  • 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: FORMULA critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
e185d9e5cbbd16be756c0e576f8642cbc665674ea4d6079bedb26d26957ee105		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 20842 bytes

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