IcedID — Office (OOXML) malware analysis

Static analysis result for SHA-256 1b8fe9a425c31361…

MALICIOUS

Office (OOXML)

186.6 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: cd658528ae60ee0da4d5fb180dab6c64 SHA-1: 18eb60f99c3b4b09b51885c6218be821cc235435 SHA-256: 1b8fe9a425c31361d3116097ea97b0daccdbfadc7ba5289a1bc59192b81a7dba
242 Risk Score

Malware Insights

IcedID · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros, specifically using dangerous formula APIs like CALL and EXEC. These macros are designed to download a file named 'NACHILE.dll' from 'http://clientportal.download/div.php' and then execute it using 'regsvr32'. This behavior is consistent with the IcedID malware family, which often uses macro-enabled documents as a delivery mechanism.

Heuristics 5

  • Excel 4.0 macro sheet (3 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 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://clientportal.download/div.php
    • 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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
e9d97d649b34346bcb4bd0af3ec29988fb7110472ea624571a0deab2bf2ddcf0		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 1008 bytes
xlm_sheet_01.xml
ee5b04b8f330ce3b38b1a1c9ced2c24cbcea9c511e23ef82cbed8244f2af6f15		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1389 bytes
xlm_sheet_02.xml
d5692bc5ce8070c4b9377e31129ace6dfc890572ab59d199fb9e9bd516cb016f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1659 bytes

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