Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 892991d1cd9604c6…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:43:41 Authoring application: Microsoft Excel First seen: 2021-11-03
MD5: 0a6a164daa324ed436b09ac4f08ac0c5 SHA-1: feaa72fa757a88b99be4f00b489ebb2bda86a75e SHA-256: 892991d1cd9604c655403f671544a93e8f2d83449abc9ce3b1e205f511509c13
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. Heuristics indicate the presence of an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The macro sheet contains references to dangerous formula APIs, suggesting it is designed to run arbitrary commands. The document body contains a large amount of seemingly random characters, which could be obfuscation or part of the macro's execution.

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) 6877 bytes
SHA-256: cae3a8803d7c7531b6c0fb3c54eb9caf433d15b5493527041ba299a4f1b76416
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 -  sXMrrplLrS
' 0018     27 LABEL : Cell Value, String Constant - AcvZqTYCRedz len=0 
' 0018     25 LABEL : Cell Value, String Constant - AhQduVkQLj len=0 
' 0018     21 LABEL : Cell Value, String Constant - AQUhzX len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G135 
' 0018     21 LABEL : Cell Value, String Constant - CEwYFb len=0 
' 0018     26 LABEL : Cell Value, String Constant - dQpVqTaPENi len=0 
' 0018     26 LABEL : Cell Value, String Constant - ExFLqIKwAGB len=0 
' 0018     26 LABEL : Cell Value, String Constant - guBEYPfRAEX len=0 
' 0018     25 LABEL : Cell Value, String Constant - IAXNudshsf len=0 
' 0018     21 LABEL : Cell Value, String Constant - IjPsZf len=0 
' 0018     23 LABEL : Cell Value, String Constant - ipTHcweA len=0 
' 0018     20 LABEL : Cell Value, String Constant - JgMNe len=0 
' 0018     23 LABEL : Cell Value, String Constant - KHcWSyCr len=0 
' 0018     21 LABEL : Cell Value, String Constant - KpGGXd len=0 
' 0018     24 LABEL : Cell Value, String Constant - NPIqOAvQN len=0 
' 0018     27 LABEL : Cell Value, String Constant - PrixVbHOfmwi len=0 
' 0018     21 LABEL : Cell Value, String Constant - SUwnID len=0 
' 0018     23 LABEL : Cell Value, String Constant - TNqsGChp len=0 
' 0018     26 LABEL : Cell Value, String Constant - TwYUvqpxwIg len=0 
' 0018     26 LABEL : Cell Value, String Constant - uFsyMExBIuY len=0 
' 0018     22 LABEL : Cell Value, String Constant - wQDceOd 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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