Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 487f1271d4f98f58…

MALICIOUS

Office (OLE)

92.0 KB Created: 2010-03-22 00:33:09 Authoring application: Microsoft Excel First seen: 2019-10-01
MD5: c1110570d6ad8364c4949a97bed2a175 SHA-1: 4225ca9b6f3e230f2f131ce2a5551c62e1c79a3c SHA-256: 487f1271d4f98f5849227d1630c48e6874c29af2d40e0f56e0513bf32870b202
260 Risk Score

Malware Insights

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 an Auto_Open macro that uses dangerous functions like RUN. This strongly suggests the file is designed to execute arbitrary code upon opening. ClamAV also identifies it as a dropper, reinforcing the likelihood of it downloading and executing a secondary payload.

Heuristics 5

  • ClamAV: Xls.Dropper.Agent-7010626-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7010626-0
  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Legacy Excel formula macro virus marker critical OLE_XLS_FORMULA_MACRO_VIRUS
    Workbook stream contains self-identifying legacy Excel formula macro virus markers. This indicates the document carries formula macro virus content even when no VBA project or modern XLM macro-sheet structure is present.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 58253 bytes
SHA-256: 74b43d4a3a4ef5aff630b596f6e838bfec7399eb508cb450a9245778093318e3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, hidden -  00000pp
' 0018     31 LABEL : Cell Value, String Constant - _Fill hidden len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x02\x00m\x00m\x00m\x00m\x00'
' 0018     32 LABEL : Cell Value, String Constant - aiu_bottom len=7 ptgRefErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x08\x00\t\t\t\t'
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 2 Auto_Close len=7 ptgRef3d 12!C4 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d 12!C4 
' 0018     26 LABEL : Cell Value, String Constant - Bust len=7 ptgRef3d 12!C31 
' 0018     30 LABEL : Cell Value, String Constant - Continue len=7 ptgRef3d 12!C9 
' 0018    103 LABEL : Cell Value, String Constant - Document_array len=8 ptgArrayA  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x01\x00\x00\xc8\x8a\x99\x02'
' 0018     41 LABEL : Cell Value, String Constant - Documents_array len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x0c\x00\x00\x00\x0f\x00\x01\x00\x01\x00'
' 0018     25 LABEL : Cell Value, String Constant - FRC len=7 ptgRef3d 4!C9 
' 0018     27 LABEL : Cell Value, String Constant - Hello len=7 ptgRef3d 12!A15 
' 0018     29 LABEL : Cell Value, String Constant - hostfee len=7 ptgRef3d 8!H12 
' 0018     34 LABEL : Cell Value, String Constant - hraiu_bottom len=7 ptgRefErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x08\x00\n\n\n\n'
' 0018     26 LABEL : Cell Value, String Constant - hvac len=7 ptgRefErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x08\x00\x12\x12\x12\x12'
' 0018     25 LABEL : Cell Value, String Constant - HWSheet len=3 ptgInt 1 
' 0018     28 LABEL : Cell Value, String Constant - MakeIt len=7 ptgRef3d 12!A26 
' 0018     37 LABEL : Cell Value, String Constant - Module.Prix_SMC len=7 ptgNameX  NAMEIDX 16 
' 0018     29 LABEL : Cell Value, String Constant - Morning len=7 ptgRef3d 12!C39 
' 0018     31 LABEL : Cell Value, String Constant - OLE_LINK1 len=7 ptgRef3d  Sheet!N194 
' 0018     28 LABEL : Cell Value, String Constant - OS len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x03\x00\x05\x80\x05\x80\x05\x80\x05\x80'
' 0018     29 LABEL : Cell Value, String Constant - PA7 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\xa3\x02\xa3\x02\xa3\x02\xa3\x02'
' 0018     29 LABEL : Cell Value, String Constant - PA8 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\xd8\x02\xd8\x02\xd8\x02\xd8\x02'
' 0018     29 LABEL : Cell Value, String Constant - PD1 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00S\x05S\x05S\x05S\x05'
' 0018     30 LABEL : Cell Value, String Constant - PE12 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\xf0\t\xf0\t\xf0\t\xf0\t'
' 0018     30 LABEL : Cell Value, String Constant - PE13 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\x99\n\x99\n\x99\n\x99\n'
' 0018     29 LABEL : Cell Value, String Constant - PE6 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\x0c\t\x0c\t\x0c\t\x0c\t'
' 0018     29 LABEL : Cell Value, String Constant - PE7 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00E\tE\tE\tE\t'
' 0018     29 LABEL : Cell Value, String Constant - PE8 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00~\t~\t~\t~\t'
' 0018     29 LABEL : Cell Value, String Constant - PE9 len=11 ptgAreaErr3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x05\x00\xb7\t\xb7\t\xb7\t\xb7\t'
' 0018     29 LABE
... (truncated)

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