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

Static analysis result for SHA-256 4e6742abd528f0b8…

MALICIOUS

Office (OOXML) / .XLSM

136.0 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: dd979ded8c91f7eb046d682da8e7f3ce SHA-1: 7ed8ad35f8e7dc105fe4bcb923ca3a8abf33ea55 SHA-256: 4e6742abd528f0b80b7583de480c6224253decc8bb0da3985c1ad13c7a1be46d
268 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous API functions like FORMULA and REGISTER, and contain strings for URLDownloadToFileA, indicating an intent to download and execute a second-stage payload. The presence of multiple suspicious URLs further supports this. The macros are hidden in multiple sheets, a common tactic to evade detection.

Heuristics 7

  • Excel 4.0 macro sheet (4 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, REGISTER, GOTO, 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.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • 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 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://188.127.251.74/44300,5396033565.dat
    • http://45.153.229.88/44300,5396033565.dat
    • http://190.14.37.188/44300,5396033565.dat
    • http://188.127.251.74/
    • http://45.153.229.88/
    • http://190.14.37.188/
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
ca9c9c5ec9e91b5ea2b16cabc4f27cbcd426710961a9cad9ff9bb338d78e5acf		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 3918 bytes
xlm_sheet_01.xml
afeb1295613a8ab2627b16d7091fa0c2905596bc8835042101146c834e6aef09		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1891 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).
xlm_sheet_02.xml
5e1bf545724a10bc5df2991eba8d56aa697917e5e2a8a36070e197b30c0df4d1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1874 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).
xlm_sheet_03.xml
466b1ed98df7ebc53dcfdf63f6856fd36890ecfbbd078bfad1c05337f7f3f128		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1915 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).

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