Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aaf2d87a1b41aaa0…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:34:03 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: 0d4a1f616a60701cce4bb004681eefea SHA-1: 6a122ba02a5f09bd85d89314767cf132dd2f57a1 SHA-256: aaf2d87a1b41aaa0ec215ad400f465655934a93f70e642dce42b9254edc3f20c
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Static analysis detected an Auto_Open defined name, which is a common technique for automatically executing malicious code when the workbook is opened. The presence of dangerous formula APIs like RUN indicates the macro is designed to execute arbitrary commands, likely leading to further stages of infection.

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) 6637 bytes
SHA-256: 92a1cad4e5d793ce00ad8289aaa72c60d3bb8e9f6e1fd18e1c3614ced62f20e7
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  bekBhYqhef
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D156 
' 0018     23 LABEL : Cell Value, String Constant - BUeYULlh len=0 
' 0018     21 LABEL : Cell Value, String Constant - CqGlhH len=0 
' 0018     23 LABEL : Cell Value, String Constant - dhaDBluW len=0 
' 0018     25 LABEL : Cell Value, String Constant - eaNfMwaLOm len=0 
' 0018     22 LABEL : Cell Value, String Constant - eyxNRaq len=0 
' 0018     24 LABEL : Cell Value, String Constant - EZaWgKjKh len=0 
' 0018     20 LABEL : Cell Value, String Constant - fvzGt len=0 
' 0018     22 LABEL : Cell Value, String Constant - GZeKcEX len=0 
' 0018     27 LABEL : Cell Value, String Constant - HBQTrEBdkTwn len=0 
' 0018     22 LABEL : Cell Value, String Constant - hcaPjHO len=0 
' 0018     27 LABEL : Cell Value, String Constant - LJghDsjFiNhp len=0 
' 0018     21 LABEL : Cell Value, String Constant - MriMWt len=0 
' 0018     22 LABEL : Cell Value, String Constant - ncruyUW len=0 
' 0018     25 LABEL : Cell Value, String Constant - OzIMBXQGrS len=0 
' 0018     21 LABEL : Cell Value, String Constant - PRSofJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - QiaZaQq len=0 
' 0018     27 LABEL : Cell Value, String Constant - slggOpgzHzqx len=0 
' 0018     23 LABEL : Cell Value, String Constant - xrfztJiH len=0 
' 0018     23 LABEL : Cell Value, String Constant - zcCINbhO len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZshcC 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     10 LA
... (truncated)

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