Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f40c056a8767bc57…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:55 Authoring application: Microsoft Excel First seen: 2021-05-26
MD5: cb11bf87769d575e07ae19357796660f SHA-1: eec7717e53200d7355b0a7ccbf6423ae21771652 SHA-256: f40c056a8767bc57354b8ab8faeedab3772c765bc1caaaf7a152925c7709e72d
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. The macro sheet itself contains a large amount of obfuscated data, likely to hide the malicious payload.

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) 6530 bytes
SHA-256: 733f5c050f8a38e31cca0131fcb9b77c6e1b592cf99639e7461f77d0299bb12a
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 -  ikUCJm
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B179 
' 0018     24 LABEL : Cell Value, String Constant - dhLACqdAO len=0 
' 0018     23 LABEL : Cell Value, String Constant - DqESnpla len=0 
' 0018     21 LABEL : Cell Value, String Constant - dXpQaC len=0 
' 0018     27 LABEL : Cell Value, String Constant - gFUkTGhhSCzO len=0 
' 0018     25 LABEL : Cell Value, String Constant - GJLyEsUBbc len=0 
' 0018     27 LABEL : Cell Value, String Constant - hJcfhIAAFcnZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - LuprH len=0 
' 0018     27 LABEL : Cell Value, String Constant - omqCtzPuYoVY len=0 
' 0018     26 LABEL : Cell Value, String Constant - PbaCjUUvjFP len=0 
' 0018     22 LABEL : Cell Value, String Constant - PieQPVR len=0 
' 0018     26 LABEL : Cell Value, String Constant - qAAuvsYAFlN len=0 
' 0018     23 LABEL : Cell Value, String Constant - QtRRZaCv len=0 
' 0018     26 LABEL : Cell Value, String Constant - rAHEtItLUuk len=0 
' 0018     25 LABEL : Cell Value, String Constant - SDDIXJIagh len=0 
' 0018     26 LABEL : Cell Value, String Constant - tCckJzozTBx len=0 
' 0018     20 LABEL : Cell Value, String Constant - uxGjC len=0 
' 0018     27 LABEL : Cell Value, String Constant - WNDPgWRVAMWy len=0 
' 0018     27 LABEL : Cell Value, String Constant - YDTGIzslYhWX len=0 
' 0018     20 LABEL : Cell Value, String Constant - ySZPq len=0 
' 0018     27 LABEL : Cell Value, String Constant - zALGIlcunxmA 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 Const
... (truncated)

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