Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b36588b490ebdcc0…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:33 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: ecdd2d6d2eb10bb779fc51579148f3aa SHA-1: e845492c21ae581bbbf6b0788bd6082643a48cf0 SHA-256: b36588b490ebdcc09f936d417537781bdda4fb1bc5c14a89fd8465efe0f58042
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The presence of dangerous formula APIs like RUN indicates an intent to execute arbitrary commands. The macro sheet itself contains obfuscated data, suggesting an attempt to hide its malicious 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) 6470 bytes
SHA-256: bda40cdab3b9646a3803fb02c278afc565b5d152776df01e74028a5a7bd76ad6
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 -  vpDUp
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G174 
' 0018     24 LABEL : Cell Value, String Constant - baUUAlUBa len=0 
' 0018     20 LABEL : Cell Value, String Constant - BFdgC len=0 
' 0018     26 LABEL : Cell Value, String Constant - epSnatkyaPQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - gaBzNsSF len=0 
' 0018     21 LABEL : Cell Value, String Constant - GbVbZF len=0 
' 0018     27 LABEL : Cell Value, String Constant - LRrVqmvXkdWx len=0 
' 0018     27 LABEL : Cell Value, String Constant - lwDkabwMjjIT len=0 
' 0018     20 LABEL : Cell Value, String Constant - MbvFn len=0 
' 0018     20 LABEL : Cell Value, String Constant - NHbgF len=0 
' 0018     24 LABEL : Cell Value, String Constant - nrvshVpAi len=0 
' 0018     22 LABEL : Cell Value, String Constant - OfGdwhi len=0 
' 0018     24 LABEL : Cell Value, String Constant - oPTLkRAbg len=0 
' 0018     25 LABEL : Cell Value, String Constant - PaNMoIhgHY len=0 
' 0018     22 LABEL : Cell Value, String Constant - rpMvKqX len=0 
' 0018     26 LABEL : Cell Value, String Constant - SSWunNreJOl len=0 
' 0018     24 LABEL : Cell Value, String Constant - syxIOmCMj len=0 
' 0018     26 LABEL : Cell Value, String Constant - TBDFLjLavLY len=0 
' 0018     23 LABEL : Cell Value, String Constant - uirQYFXa len=0 
' 0018     22 LABEL : Cell Value, String Constant - WJZdxYY len=0 
' 0018     27 LABEL : Cell Value, String Constant - zdZokOVLiyjj 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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