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

Static analysis result for SHA-256 8203d7f821b46260…

MALICIOUS

Office (OOXML) / .XLSM

660.7 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: bd2d5129f9d0e0d3d987adcfe1ca0e9c SHA-1: 133025553eed6bb342131e029e9b4dc53f0db004 SHA-256: 8203d7f821b46260d541ebac2ff8d05be1052e86d500ecddb0010f855943e179
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros, which are known to be used for malware delivery. The macros use dangerous functions like REGISTER and EXEC to call Win32 APIs, indicating an intent to download and execute a second-stage payload from the embedded URLs. The use of hidden sheets further suggests an attempt to conceal malicious activity.

Heuristics 5

  • Excel 4.0 macro sheet (2 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: REGISTER, RUN, EXEC, HALT 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.
  • 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://104.168.166.222/images/darkmoonlite.png
    • http://104.168.166.222/images/shortearthget.png
    • http://104.168.166.222/images/lovemetertok.png
    • http://schemas.openxmlformats.org/spreadsheetml/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/excel/2006/main
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
40ddb28feb0f81c4ec854fd8ba2b194a30a086ab4790b6dad4d44c8b8ae4ad9f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 2083 bytes
xlm_sheet_01.xml
24a9abf86273767cb6dc3ef5123101e29e32d244c5f84ae5cf491b44ffd6397a		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1651 bytes

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