IcedID — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 5cb9927ce68fc679…

MALICIOUS

Office (OOXML) / .XLSM

170.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 8c1f919922567e264bb716f19dc2b017 SHA-1: b42e542b64f89cc6e0947a3a47a60f73fec326e5 SHA-256: 5cb9927ce68fc679a59c3256d07295ebdcb9481f88541da49d410d2a9d169197
242 Risk Score

Malware Insights

IcedID · confidence 95%

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

The file is an XLSM document containing Excel 4.0 macros, identified by the 'OOXML_XLM_MACROSHEET' heuristic. These macros utilize dangerous functions like FORMULA.FILL, GOTO, RETURN, and EXEC to download and execute a payload from the URLs http://188.127.227.99/ and 45.150.67.29/. The ClamAV detection 'Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0' strongly suggests the IcedID family.

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
21b43b24fc2a4b371e0eab7f7cbec4533426891fb10a2e0ff24cac569d7b0f37		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5565 bytes
xlm_sheet_01.xml
5c4423f87de4646755545b93c22f66e76828f61098e22de81e80e42a48f190a9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2434 bytes

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