Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bec5c1e6f5b9e666…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:27:25 Authoring application: Microsoft Excel First seen: 2021-09-16
MD5: 617529a4f04ced8a829d906b6744edd2 SHA-1: 3f9f8c6726f1507d2e09921c8d9bbe1bb50cc0e6 SHA-256: bec5c1e6f5b9e66686f6fce87d15770b6c8debac2d930e68a2582a1f3508c5c3
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically triggering an Auto_Open function. This function is known to be used for executing malicious code upon opening the document. The presence of dangerous formula APIs further indicates 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) 6625 bytes
SHA-256: fe48352c4aefcceb7b0935cfa5866a923764069fcddf34eeb0fc8917b8266fc2
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  rhgdflaGd
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C195 
' 0018     22 LABEL : Cell Value, String Constant - axCAXVa len=0 
' 0018     22 LABEL : Cell Value, String Constant - bVlTzJp len=0 
' 0018     25 LABEL : Cell Value, String Constant - cKKjBqZBLz len=0 
' 0018     20 LABEL : Cell Value, String Constant - DCdLZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - eivIH len=0 
' 0018     27 LABEL : Cell Value, String Constant - HHEbWnEemClE len=0 
' 0018     20 LABEL : Cell Value, String Constant - JndPH len=0 
' 0018     22 LABEL : Cell Value, String Constant - JRHyrDO len=0 
' 0018     23 LABEL : Cell Value, String Constant - JYxIhuad len=0 
' 0018     21 LABEL : Cell Value, String Constant - LcFymc len=0 
' 0018     26 LABEL : Cell Value, String Constant - LNHuNReQSRA len=0 
' 0018     24 LABEL : Cell Value, String Constant - oSFZKGTVq len=0 
' 0018     25 LABEL : Cell Value, String Constant - OTYEMzdqej len=0 
' 0018     22 LABEL : Cell Value, String Constant - SouALHg len=0 
' 0018     26 LABEL : Cell Value, String Constant - vCXKPwTRzsY len=0 
' 0018     26 LABEL : Cell Value, String Constant - VWyLLmGoiij len=0 
' 0018     27 LABEL : Cell Value, String Constant - vyHWREQWcENe len=0 
' 0018     22 LABEL : Cell Value, String Constant - XplsyDK len=0 
' 0018     21 LABEL : Cell Value, String Constant - zDgzaB len=0 
' 0018     21 LABEL : Cell Value, String Constant - zpAhWC 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 L
... (truncated)

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