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

Static analysis result for SHA-256 0beb60755fc445dd…

MALICIOUS

Office (OOXML) / .XLSM

79.8 KB Created: 2021-02-10 12:29:58 UTC Authoring application: 16.0300
MD5: 087ab72bddf5ddc2b92322833a478dd7 SHA-1: dcb02412280d83fd1d8a3d25b3bad9e3112f2425 SHA-256: 0beb60755fc445ddc00f203950e5f1e4fa65345a91103c16d9329d8592f59d1c
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros that leverage the dangerous `RETURN()` function, which can be used to call Win32 APIs. The VBA code also explicitly uses `URLDownloadToFileA`, indicating an intent to download and execute a second-stage payload from a remote source. The presence of both XLM and VBA macros suggests a multi-stage approach to achieve its malicious objective.

Heuristics 6

  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
  • 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.
  • Dangerous XLM formula APIs: RETURN 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 4 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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
macros.bas
93dd6a04e1c8847dc3bcb46aa910b0b6f137bb36204e9deaa7e2933cbbc93734		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3924 bytes
vbaProject_00.bin
d5a1287bfac2e7cf5777d15e3599bb3214f5463a0615a612e8d2ec1b57bd519f		 vba-project OOXML VBA project: xl/vbaProject.bin 25600 bytes
xlm_sheet_00.xml
e4d5ed32618eb4dd5e368d0c0a92dde4c221eb4d71d635dcc1ba0e4cf3875218		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1055 bytes

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