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

Static analysis result for SHA-256 c3e43a7fe54642d5…

MALICIOUS

Office (OOXML) / .XLSM

170.9 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 2ed585fda4f279315191cdac2b0b9897 SHA-1: ead4a8c23d673920530312f70d774aa28e4c0349 SHA-256: c3e43a7fe54642d5dd3f4ae6412ca6195f5ac6972072c8e3503d5887eeba0759
250 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

This XLSM file contains Excel 4.0 macros, indicated by multiple heuristic firings including 'OOXML_XLM_MACROSHEET' and 'OOXML_XLM_AUTOOPEN_DEFINEDNAME'. The macros utilize dangerous XLM formula APIs like FORMULA, GOTO, and HALT, which are commonly used to download and execute malicious payloads. The ClamAV detection 'Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0' further supports its role as a downloader.

Heuristics 6

  • Excel 4.0 macro sheet (6 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, GOTO, 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.
  • ClamAV: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 6 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 — context-specific rules above attribute URLs they actually evaluated; this rule lists URLs that were present in the bytes but were not otherwise tied to a specific finding.
    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/excel/2006/main
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
e26278d9df62929caddc39c2675d1a93c805965a35896b4c4240468b728373e2
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 1190 bytes
xlm_sheet_01.xml
5f4ba7159c1da7e493848f74e3669405dc7409a06e720ced64dc3eb8a5827a76
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 2902 bytes
xlm_sheet_02.xml
f29a49c753318e85f442bed44c64f292c1b7fd6c5ed8b8668c3938c69145161e
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 2297 bytes
xlm_sheet_03.xml
966a712c4f0f0d2f58ef2ea09ca169fd5d5278d9396ce226e09ea14a32d1074e
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml 1477 bytes
xlm_sheet_04.xml
84368b896055b80ba37112653973d9ab4ada45ec06389956e8791ed998edcdc5
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.xml 1451 bytes
xlm_sheet_05.xml
68e2eada477a01dd45889d7781ac27297df589224a5824d7ff63a37df7f5bc75
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1476 bytes