Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c00271ccd7ea7391…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:46:34 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: ee6668e966011fe73cd2316a9c864bda SHA-1: 2339641db2f880de19b86367048cd086e6eb509e SHA-256: c00271ccd7ea739172c1af6525e78cc29c95f23d642686155623b1657e37fc00
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry point, suggesting an attempt to automatically execute code when the workbook is opened. The macro sheet itself contains obfuscated data, and the Auto_Open function likely leverages dangerous formula APIs to achieve execution. This points to a macro-based execution technique, common in initial compromise stages.

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) 6464 bytes
SHA-256: 7f8ecdc6e7f758ee2df5e73586fec225fed8e028d46ff8e879f498326d3cc8a6
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Ceg
' 0018     23 LABEL : Cell Value, String Constant - AdazOjzb len=0 
' 0018     20 LABEL : Cell Value, String Constant - aTCcw len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G188 
' 0018     26 LABEL : Cell Value, String Constant - AVsSfBygfDY len=0 
' 0018     20 LABEL : Cell Value, String Constant - BDuWQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - CazRwEx len=0 
' 0018     26 LABEL : Cell Value, String Constant - CRADECEGvYT len=0 
' 0018     27 LABEL : Cell Value, String Constant - dPbCcTunIyWx len=0 
' 0018     24 LABEL : Cell Value, String Constant - FmskzQuau len=0 
' 0018     23 LABEL : Cell Value, String Constant - HukWyqwB len=0 
' 0018     27 LABEL : Cell Value, String Constant - idkrNPiPSfJW len=0 
' 0018     20 LABEL : Cell Value, String Constant - ipfsV len=0 
' 0018     24 LABEL : Cell Value, String Constant - jlKjGvyXf len=0 
' 0018     23 LABEL : Cell Value, String Constant - mDPEzWiF len=0 
' 0018     26 LABEL : Cell Value, String Constant - mfKIXfhEamH len=0 
' 0018     23 LABEL : Cell Value, String Constant - PDukjDAp len=0 
' 0018     26 LABEL : Cell Value, String Constant - PulLAycsjld len=0 
' 0018     27 LABEL : Cell Value, String Constant - qiPPTEADJPsT len=0 
' 0018     27 LABEL : Cell Value, String Constant - SfbZOOOQjjqb len=0 
' 0018     27 LABEL : Cell Value, String Constant - uvzvmoeaVkFc len=0 
' 0018     22 LABEL : Cell Value, String Constant - zjiJQTo 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 Constant/ SST

... (truncated)

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