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

Static analysis result for SHA-256 18df9c0f62f91867…

MALICIOUS

Office (OOXML) / .XLSX

14.3 KB Created: 2020-05-21 01:21:29 UTC Authoring application: Microsoft Excel 16.0300
MD5: c3ddbc677b4ef58740b4aa26a3d80235 SHA-1: 67ec3ae7a8507e042f954968849345d8342b1865 SHA-256: 18df9c0f62f918672a0d87c92a5a28d43239cb345bd502b3c4207ea62649cece
222 Risk Score

Malware Insights

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

The sample is an Excel file containing a Workbook_Open macro that executes obfuscated VBA code. This code appears to be designed to download and execute a second-stage payload via the Shell() function. The presence of both VBA and XLM macros suggests a multi-stage attack leveraging different Excel macro capabilities.

Heuristics 6

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
2127df5c71bb161ed96591cdb7585bd3289aff3fe4cee84fb7c59189e66d3d6a		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2943 bytes
vbaProject_00.bin
9fa5da98bec1e7a0c73e776b35cc1273a5b024df181b13d5e1db6e93ef3258fd		 vba-project OOXML VBA project: xl/vbaProject.bin 12288 bytes
xlm_sheet_00.xml
9673101e2c1e6c26a2ca3714b75a951dc7cabcc55d417a781c60662ae60ae196		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1199 bytes

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