Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a737d748594985cd…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:26:14 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: b51282a84d1b5d1b72cef71565fe26cf SHA-1: 5fa52697fab9ba8734374510c877305b5d992738 SHA-256: a737d748594985cd3eec053cc4b1aea90b9ed7b72657eafba010c54b4b4bc3f9
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 (XLM) macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The presence of an Auto_Open defined name suggests that the macro will execute automatically when the workbook is opened. The dangerous formula APIs used in the macro are a strong indicator of malicious intent, likely to download and execute a secondary 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) 6444 bytes
SHA-256: 7a97da930e34807442ca39aaa27f819b517050f74916d6a12d1b1414df4f951e
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 - Excel 4.0 macro sheet, visible -  swpyL
' 0018     27 LABEL : Cell Value, String Constant - AqnyCVyvADcE len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I161 
' 0018     23 LABEL : Cell Value, String Constant - CdvdXhNI len=0 
' 0018     24 LABEL : Cell Value, String Constant - FOdWURkvt len=0 
' 0018     25 LABEL : Cell Value, String Constant - hjSwhhBmpu len=0 
' 0018     21 LABEL : Cell Value, String Constant - iiHLHX len=0 
' 0018     27 LABEL : Cell Value, String Constant - ltZiofceyHlJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - MWmSe len=0 
' 0018     20 LABEL : Cell Value, String Constant - nYMPt len=0 
' 0018     20 LABEL : Cell Value, String Constant - oeFMu len=0 
' 0018     27 LABEL : Cell Value, String Constant - plQQBhkhzlkM len=0 
' 0018     26 LABEL : Cell Value, String Constant - QNqAvQPRHOg len=0 
' 0018     22 LABEL : Cell Value, String Constant - QrqYcGi len=0 
' 0018     24 LABEL : Cell Value, String Constant - SYTMLQysm len=0 
' 0018     26 LABEL : Cell Value, String Constant - tfLWzZKIIbQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - UxWrWuMBXRLA len=0 
' 0018     21 LABEL : Cell Value, String Constant - vogrGI len=0 
' 0018     27 LABEL : Cell Value, String Constant - VxcFGaADdNcr len=0 
' 0018     27 LABEL : Cell Value, String Constant - weWFpXYriGwf len=0 
' 0018     21 LABEL : Cell Value, String Constant - XJpTwn len=0 
' 0018     20 LABEL : Cell Value, String Constant - YSVHY 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
' 00fd
... (truncated)

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