Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 988a5fc85dfeaa3f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:16 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: 4b4881618a5a6507f777e5c35f51f752 SHA-1: 77f40626a518305be13c81edc8785e470b2b2dcd SHA-256: 988a5fc85dfeaa3f5add283670f1cb4eba93f787a27508c078e37a53c986e0a0
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 (XLM) macros, specifically an Auto_Open macro. This indicates an attempt to automatically execute code when the file is opened. The presence of dangerous formula APIs like RUN suggests the macro is intended 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) 6703 bytes
SHA-256: 8d481a68de7d60833ca721913f709d70050a95c6ef683a84b73118500f68f6e6
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  XYLaiSpuNtR
' 0018     23 LABEL : Cell Value, String Constant - ANvkrKWL len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C203 
' 0018     27 LABEL : Cell Value, String Constant - bOWEcSsDrVTj len=0 
' 0018     24 LABEL : Cell Value, String Constant - byJdyUtOD len=0 
' 0018     23 LABEL : Cell Value, String Constant - DeUwaolB len=0 
' 0018     26 LABEL : Cell Value, String Constant - DGOcjsbaGOi len=0 
' 0018     26 LABEL : Cell Value, String Constant - eaZkMuNhSLv len=0 
' 0018     20 LABEL : Cell Value, String Constant - LEOQP len=0 
' 0018     22 LABEL : Cell Value, String Constant - mYWYyZg len=0 
' 0018     22 LABEL : Cell Value, String Constant - OyuWgQS len=0 
' 0018     22 LABEL : Cell Value, String Constant - pLczjRE len=0 
' 0018     26 LABEL : Cell Value, String Constant - QkmawxgFiNY len=0 
' 0018     22 LABEL : Cell Value, String Constant - reIwJGp len=0 
' 0018     23 LABEL : Cell Value, String Constant - tHZAgpKr len=0 
' 0018     26 LABEL : Cell Value, String Constant - tUUkXzhCICi len=0 
' 0018     24 LABEL : Cell Value, String Constant - uzdMUZjjN len=0 
' 0018     21 LABEL : Cell Value, String Constant - vSjeAI len=0 
' 0018     23 LABEL : Cell Value, String Constant - WaqzviyT len=0 
' 0018     23 LABEL : Cell Value, String Constant - YIvmNwlO len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZdYMiDhfdn len=0 
' 0018     23 LABEL : Cell Value, String Constant - ztjCnESC 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
' 00
... (truncated)

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