IcedID — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 1a7f65308ac3a4f9…

MALICIOUS

Office (OOXML) / .XLSM

170.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 803abe40999790e0642e5a93221da062 SHA-1: 0b9f5658c091de7c07823e5aba25a5d760231d8f SHA-256: 1a7f65308ac3a4f9765902061157d7255abc8a72b38b5c230e4666a7fe5b0028
240 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Micro Focus Directory Services T1204.002 Malicious File: User Execution

The file is an XLSM document containing Excel 4.0 macros, as indicated by multiple critical heuristic firings. These macros utilize dangerous functions like FORMULA.FILL, GOTO, RETURN, and EXEC, which are known primitives for downloading and executing payloads. The embedded URL in the document body likely points to the second-stage payload. The ClamAV detection explicitly names this as IcedID, a known banking trojan.

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
beaf3ffbc0c1fe0940b468bbe018294b2e9df57ed661175b2b23a1d74554dc29
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 5720 bytes
xlm_sheet_01.xml
24891294ef37aa1a32df25cf488687c1f0e2acd16ce43be5b9a0be75f6fdd1ba
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2124 bytes