IcedID — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 f57fcd2b9424dafe…

MALICIOUS

Office (OOXML) / .XLSM

170.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 6c31bd9a699b8cfbe17bdcd6d83bd427 SHA-1: 2c803606b88254b5f209de7f66364ee5c81c1414 SHA-256: f57fcd2b9424dafe82133f9a4646b7b53ddb55676bc50070ed0668f5da9d5c68
328 Risk Score

Malware Insights

IcedID · confidence 95%

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

The file is an XLSM document containing Excel 4.0 macros, which is a known delivery mechanism for IcedID. Critical heuristics indicate the use of dangerous XLM functions like FORMULA, REGISTER, and EXEC, along with WinAPI strings such as URLDownloadToFileA. These functions are used to download and execute a second-stage payload from the provided URLs. The ClamAV detection also confirms the IcedID family.

Heuristics 8

  • Excel 4.0 macro sheet (4 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, REGISTER, GOTO, EXEC, 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.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • ClamAV: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.IcedID-9f1f1d193a2a2a2b-9951463-0
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 4 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 — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://37.46.133.194/44285,5327891204.dat
    • http://185.212.129.66/44285,5327891204.dat
    • http://190.14.37.248/44285,5327891204.dat
    • http://37.46.133.194/
    • http://185.212.129.66/
    • http://190.14.37.248/
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
c876972a17f6d5428b7bc5b30c452b884a0c90c1627fdd8d3512762830a5a181		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 3899 bytes
xlm_sheet_01.xml
0968b576406b659c600cdff11889e4d244b800464c83754b17dd997ba50016cb		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2166 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).
xlm_sheet_02.xml
56334bdc18b65ce35335d877bd118ba34743a2b806892d2371f6613aab8e0bd9		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 2034 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).
xlm_sheet_03.xml
1c0bd40302a873a5eb674957d440761136078e201cfafd988e6c47500f34fe51		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 2011 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s).

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