Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d7ba69b901a629cf…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:42:43 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: 3b2ececabefec72d4d56e647504f66dd SHA-1: 5d16bccc8b2153971a0edb86fb754fd11f19310b SHA-256: d7ba69b901a629cfe37891a2d5b6c515b9b01024cc72695e22d0512f77793d89
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical finding indicating potential malicious execution. The presence of dangerous formula APIs like RUN further supports this. The macro sheet itself is named 'TUAgvb', and the Auto_Open entry points to a cell that likely contains the malicious code, though the exact payload is truncated in the provided evidence.

Heuristics 3

  • 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.
  • 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) 6733 bytes
SHA-256: fd7a54092cbd0ea48c2c750eb17ddd9c039f53f4cfdea7dda5183c40eacecd45
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TUAgvb
' 0018     20 LABEL : Cell Value, String Constant - aOYnE len=0 
' 0018     20 LABEL : Cell Value, String Constant - AuHrc len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F162 
' 0018     23 LABEL : Cell Value, String Constant - ciTmfppF len=0 
' 0018     27 LABEL : Cell Value, String Constant - dxlNCwRQwwRY len=0 
' 0018     27 LABEL : Cell Value, String Constant - FreewnKcztbX len=0 
' 0018     26 LABEL : Cell Value, String Constant - GcyNYAmxgYr len=0 
' 0018     27 LABEL : Cell Value, String Constant - gogqrVvLvtic len=0 
' 0018     26 LABEL : Cell Value, String Constant - joYuqJLlFLu len=0 
' 0018     24 LABEL : Cell Value, String Constant - MgqOpGBKh len=0 
' 0018     26 LABEL : Cell Value, String Constant - mrxrUuwXuCO len=0 
' 0018     20 LABEL : Cell Value, String Constant - ncigF len=0 
' 0018     23 LABEL : Cell Value, String Constant - oJZesmxa len=0 
' 0018     26 LABEL : Cell Value, String Constant - oYWYFtwIlVh len=0 
' 0018     22 LABEL : Cell Value, String Constant - PqHMFjB len=0 
' 0018     27 LABEL : Cell Value, String Constant - qsDLKnzCJxcy len=0 
' 0018     27 LABEL : Cell Value, String Constant - RjAnflXQSxtW len=0 
' 0018     27 LABEL : Cell Value, String Constant - RzOwuMHyinpt len=0 
' 0018     25 LABEL : Cell Value, String Constant - ukXQnkBwtq len=0 
' 0018     21 LABEL : Cell Value, String Constant - yQimju len=0 
' 0018     27 LABEL : Cell Value, String Constant - zHnkIlJmCvMN len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Con
... (truncated)

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