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

Static analysis result for SHA-256 6c8c096650de2a43…

MALICIOUS

Office (OOXML) / .XLSM

158.3 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 16.0300
MD5: c018d5256df5bafb1e3dc7b6ce8baf7a SHA-1: cd698f29ed290dc0be17fdd3be97bbd6388fb6ea SHA-256: 6c8c096650de2a436770ce00e63ec380aef9f64b787d8aecb3e5b96cafad6fb1
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an XLSM document containing multiple Excel 4.0 macro sheets. Critical heuristics indicate the use of dangerous XLM formula APIs like FORMULA, HALT, and FORMULA.FILL, which are often used to download and execute payloads. The document body and embedded artifacts suggest an attempt to download files from the URLs 'https://astronomia-esp.com/j5KMREjY4/gg.html' and 'https://m-morsi.com/fDpJyn0aEyCB/gg.html' and save them as '..\cexyz2.dll' and '..\cexyz1.dll'.

Heuristics 5

  • Excel 4.0 macro sheet (5 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: FORMULA, HALT, FORMULA.FILL 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 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://astronomia-esp.com/j5KMREjY4/gg.html
    • https://m-morsi.com/fDpJyn0aEyCB/gg.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
    • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
fb11a6fcbb152db165d2a6724e880a02e36305b93a41677e2c485b8bc83bf634
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 11344 bytes
xlm_sheet_01.xml
01be081374433318ab060c7d9534b134366d414e43d756214d58deb1a7557a22
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1807 bytes
xlm_sheet_02.xml
4942d78e9a4c26c9352582ba044fbdd7b5e434ac67308d3cb59b8725b48e9b99
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1777 bytes
xlm_sheet_03.xml
a6863ce46a6a991745232b05bc1b5af380056ae05155ba24221669ae920dc1d9
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml 1460 bytes
xlm_sheet_04.xml
7a65a9a19541a783d2364e0cc237ab353fd49b12ac69aaaae5e6996c7d787d37
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml 1558 bytes