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

Static analysis result for SHA-256 24f0f50d0dd94a6d…

MALICIOUS

Office (OOXML) / .XLSM

146.7 KB Created: 2020-07-01 09:45:03 UTC Authoring application: Microsoft Excel 16.0300
MD5: fefa86d7b5dfe6bbfee0b67bb76ed055 SHA-1: cac22c01f711503f0c4a097835d0ec8ac8832105 SHA-256: 24f0f50d0dd94a6dcbef33a6abe2cf3a33a19a8752cd95a7a0a436ff1bcce618
128 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Phishing: Spearphishing Attachment T1059.005 Command and Scripting Interpreter: Visual Basic T1204.002 Malicious File Execution: Malicious File

This XLSM file contains an Excel 4.0 macro sheet, which is a known vector for malware delivery. The presence of dangerous XLM functions like FORMULA.FILL, REGISTER, and HALT indicates the macro is capable of executing arbitrary code, likely to download and run a second-stage payload. The 'Macro/content-enable lure' heuristic further suggests the document is designed to trick the user into enabling these malicious macros.

Heuristics 5

  • Dangerous XLM formula APIs: FORMULA.FILL, REGISTER, 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.
  • Excel 4.0 macro sheet (1 sheet(s)) high 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 20 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://schemas.openxmlformats.org/spreadsheetml/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/spr

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
fc91b61d73e1ea7b2b8ed74b419e4706cf6dde76f20dee32a51bdd54a6f38bae		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 38704 bytes

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