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

Static analysis result for SHA-256 06c9a8f5da75ebc7…

MALICIOUS

Office (OOXML) / .XLSM

114.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: 0276be45120eeb640587451db55759cb SHA-1: 51424cff72ecb039f78d5005a03ec2882a96d7dd SHA-256: 06c9a8f5da75ebc77f7528ceb2797050ba17cc2c7e36467b0d259d4f48dbbcbf
190 Risk Score

Malware Insights

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

The file is an XLSM document containing Excel 4.0 macros, which are known to be used for malicious purposes. The macros utilize dangerous API functions like FORMULA and EXEC to download a payload from one of the provided URLs. The presence of an Auto_Open macro further indicates malicious intent, as it automatically executes upon opening the document.

Heuristics 6

  • 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.
  • Dangerous XLM formula APIs: FORMULA, HALT, GOTO, REGISTER, 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.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 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://185.183.99.115/44313,6048108796.dat
    • http://51.89.73.159/44313,6048108796.dat
    • http://190.14.37.38/44313,6048108796.dat
    • http://185.183.99.115/
    • http://51.89.73.159/
    • http://190.14.37.38/
    • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
aa10abebc3ece39bf198cf3383ccb30417606e0a98d60e87747026c15426213c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2437 bytes
vbaProject_00.bin
91a9b7465b88e20cedc488ee563b51a66933319637de00c1bc25730d49fcda6a		 vba-project OOXML VBA project: xl/vbaProject.bin 23552 bytes
xlm_sheet_00.xml
1754d2e1b6c4f50a584bbed904e8c391f5774d8bb3d5d1aed732e1538fdab9f1		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4133 bytes
xlm_sheet_01.xml
e160b159452c58df54bac64c2408088fc69c4a427060e264cc2ce4a1856b2db2		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2129 bytes
xlm_sheet_02.xml
0b087dc342d0a7c7ecdeb426e7cbcf43637a78a1fe8870ea48fc5df73c2f7887		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1949 bytes

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