IcedID — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 c36410bf72561ae9…

MALICIOUS

Office (OOXML) / .XLSM

170.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 82fd06acb5166e0c0dbb41d419d807d7 SHA-1: 8c7a3c4eb325d0d6c874c2aa551dae98035928f8 SHA-256: c36410bf72561ae9b35ecc612f837a7ef315bb0c9d623e263bbd988f6fa95a82
240 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1105 Ingress Tool Transfer

The sample is an XLSM file containing Excel 4.0 macros, identified by the 'OOXML_XLM_MACROSHEET' heuristic. The macros utilize dangerous functions like FORMULA.FILL, GOTO, RETURN, and EXEC, which are known primitives for downloading and executing payloads. The ClamAV detection as 'Xls.Downloader.IcedID' strongly suggests the IcedID family. The document body contains IP addresses that are likely associated with the payload delivery infrastructure.

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: FORMULA.FILL, GOTO, RETURN, EXEC 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.
  • ClamAV: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0
  • 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.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
2149a78df9a4c2614a77eac7e6bea8856e83727824c7253b5852e5bc49a88bc0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5435 bytes
xlm_sheet_01.xml
544a35c39d1128d8fefaea33fca4f9da4ed2d629958b986ed71b73a0418583c0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2473 bytes

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