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

Static analysis result for SHA-256 1f13b0a5384353c1…

MALICIOUS

Office (OOXML) / .XLSM

84.0 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: 599be088d3897daf121ee7b588b219d4 SHA-1: 55e85c9456e63394beec1c17e159975c5f2bd055 SHA-256: 1f13b0a5384353c13a0a84261ec9d45bcd77fc8547acdb36f118f788317cca64
188 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Critical heuristics indicate the presence of an Auto_Open macro and the use of dangerous XLM functions like CALL and EXEC. These functions are commonly used to download and execute arbitrary code. The document body contains URLs that are likely used to host the malicious payload. The primary intent appears to be the execution of a second-stage payload via the embedded XLM macros.

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: EXEC, HALT, 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.
  • External hyperlinks (2) low OOXML_EXTERNAL_HYPERLINKS
    Document contains 2 external hyperlinks — clickable URLs are stored as external relationships. First target: http://onellahardware.com/drms/fert.html
  • 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://onellahardware.com/drms/fert.html
    • https://arsalanconsult.com/drms/fert.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
1393651a1bde2f6ba981dc167a40e0ff505627511db4c15284689f95a6e7ef49		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 6962 bytes
xlm_sheet_01.xml
c24efd13131149771b95a7e307fa52e44ef6b33bf9cdb4cb68694afb1c2158c8		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 2287 bytes

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