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

Static analysis result for SHA-256 bde3e41249165369…

MALICIOUS

Office (OOXML) / .XLSM

82.1 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 5884b147d34c8525101e6c3c13320d38 SHA-1: 5f3bfdec9266df534677837e3d9d85dad7f91372 SHA-256: bde3e41249165369201bcfe9e8e04ee189fc71b0d79ffe446c2d1d5213a693f2
180 Risk Score

Malware Insights

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

The file is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. The macros utilize dangerous API functions like CALL and FORMULA, which are often used to download and execute second-stage payloads. The presence of an Auto_Open defined name further suggests automatic execution upon opening. While specific IOCs for malicious URLs are not present, the technique itself is indicative of a downloader.

Heuristics 4

  • Excel 4.0 macro sheet (3 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, CALL, HALT, EXEC 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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
750216d98b571028196caa5db2d00d1d865d416953bfdc8d348887b876ac8299		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 19711 bytes
xlm_sheet_01.xml
d30d0bdbdc3063e69afc7d3c6401429aac87693165a049927be503c06d2c964c		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1419 bytes
xlm_sheet_02.xml
644ddaecdc2c5458cffc5ad58ed19949086a06cf10b478a5857d1c4cd8813551		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 6156 bytes

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