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

Static analysis result for SHA-256 662830791665cca4…

MALICIOUS

Office (OOXML) / .XLSM

109.5 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 0c4dce2faaa0b8df049056b766c821d3 SHA-1: 099e67bfee2536c2a9a9bca79dd54c869cb2d25e SHA-256: 662830791665cca4cffd3df764c3b86b7ffa6de1e1be5fc3f876d18596b92e24
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

This Excel 4.0 macro-enabled workbook (XLSM) contains critical heuristics indicating the use of dangerous XLM formula APIs like EXEC and CALL. The macros are designed to download and execute a second-stage payload from the URLs https://giftsonlinejo.com/drms/ind.html or https://kurtos.eu/drms/ind.html, likely using the reconstructed commands EXEC(Sheet2!AM34&"..\duron.bnm1"&,DllRegisterServer") or EXEC(Sheet2!AM34&"..\duron.bnm2"&,DllRegisterServer"). The presence of hidden sheets and the use of Auto_Open further support its malicious intent.

Heuristics 6

  • 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: EXEC, HALT, FORMULA, WORKBOOK.HIDE, CALL 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.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 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 https://giftsonlinejo.com/drms/ind.html
    • https://kurtos.eu/drms/ind.html
    • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
def365b5d7a87e6d02a6e16eb8f12a49fdc817651fd2675b7065c2f67b4c736b		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 3531 bytes
xlm_sheet_01.xml
7533330654b8e753d53bb8f9ac5e758b933e3ee32dea384bde4afa6209ed2d29		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 205649 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).

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