Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f79ca916e1e453b9…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:42:51 Authoring application: Microsoft Excel First seen: 2021-10-04
MD5: 1abedcbb8b5e43983a118d297ceccdfc SHA-1: ee4786ca5a520b0dd5f9a513d448eeceaa48562f SHA-256: f79ca916e1e453b9f6ac91fa6cb3f5d7c41dafc6536a829aa5f872fac8e6da85
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro sheet is designed to automatically execute code upon opening. The presence of dangerous formula APIs further confirms the malicious intent, likely to download and execute a second-stage 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) 6670 bytes
SHA-256: dc37398dec6f402bff4c629c51f1cb8c2aa66ed33dac9b693138273926f33910
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 -  mpqmUWGjw
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G157 
' 0018     27 LABEL : Cell Value, String Constant - bDuoTRlNmrsS len=0 
' 0018     26 LABEL : Cell Value, String Constant - CJnKGUcwgsN len=0 
' 0018     22 LABEL : Cell Value, String Constant - dYxQiPs len=0 
' 0018     24 LABEL : Cell Value, String Constant - flUhmEOtw len=0 
' 0018     26 LABEL : Cell Value, String Constant - IfofTROLrJW len=0 
' 0018     27 LABEL : Cell Value, String Constant - ISEYgiBkRjlS len=0 
' 0018     22 LABEL : Cell Value, String Constant - jFJaoyk len=0 
' 0018     20 LABEL : Cell Value, String Constant - jfUQM len=0 
' 0018     26 LABEL : Cell Value, String Constant - LxICyHjRfVK len=0 
' 0018     23 LABEL : Cell Value, String Constant - MGOCUeVb len=0 
' 0018     22 LABEL : Cell Value, String Constant - qIpogeD len=0 
' 0018     21 LABEL : Cell Value, String Constant - rpVMOQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - sOBvCko len=0 
' 0018     25 LABEL : Cell Value, String Constant - XthzErdEAY len=0 
' 0018     24 LABEL : Cell Value, String Constant - yFfBWYjZm len=0 
' 0018     22 LABEL : Cell Value, String Constant - YfqpLFg len=0 
' 0018     27 LABEL : Cell Value, String Constant - ymKLeqLLrFmM len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZBGKvgmBVO len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZnkHTQIWQojh len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZOxvxwx 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/ S
... (truncated)

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