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

Static analysis result for SHA-256 ad4a6839c1b09105…

MALICIOUS

Office (OOXML) / .XLSM

109.5 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 06652345df76d0ae5a147269f7dd4a39 SHA-1: fce31d0e86cfc80a7ee1d8ae589c3689c0b0f8af SHA-256: ad4a6839c1b09105c40ef250675319f2c6e2857484aa120459de2c8564d82baa
208 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Control T1204.002 Malicious File: User Execution T1059.001 PowerShell T1105 Ingress Tool Transfer

The sample is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. Critical heuristics indicate the use of dangerous XLM functions like CALL and EXEC, which are commonly used to download and execute payloads. The document body explicitly contains URLs that are likely used for this purpose. The presence of hidden sheets further supports the concealment of malicious activity. The primary intent appears to be downloading and executing a second-stage payload from the provided URLs.

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://immobiliareneri.casa/drms/ind.html
    • https://gidbasket.com/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
7d118572f5fe7d6ff43ed02ebd45ba65e8abef406e7a780baf6c364273fc6add		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 3454 bytes
xlm_sheet_01.xml
fbe5e7dbb69c9673a292262e360301ab1ec7a303eb74e3af592196e67c71385f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 205673 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).

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