Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d5e9784a15b427a0…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:28:54 Authoring application: Microsoft Excel First seen: 2021-10-05
MD5: 2ce89ee05bd86513072fa9ea34cca09e SHA-1: 5a0d76a57c445db7fe7cd247ceda5c4df7bd533a SHA-256: d5e9784a15b427a032d55aedb9b740834ba149f68a3ee6b75d8c31b482afffae
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 function, which is a known method for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. The macro sheet itself is named 'DfzJYlk', and the document body contains obfuscated strings that likely contribute to 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) 6456 bytes
SHA-256: caefc3e0ef6b9d5844be88fd6c8b4f202a1114206a6ae9cc625b861d5ca4aa05
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  DfzJYlk
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D178 
' 0018     22 LABEL : Cell Value, String Constant - BRLAwXb len=0 
' 0018     24 LABEL : Cell Value, String Constant - CgtIPzmuW len=0 
' 0018     26 LABEL : Cell Value, String Constant - DcxXJmDDzoL len=0 
' 0018     23 LABEL : Cell Value, String Constant - fnPGercu len=0 
' 0018     22 LABEL : Cell Value, String Constant - FRmEJcx len=0 
' 0018     21 LABEL : Cell Value, String Constant - IVBZXp len=0 
' 0018     27 LABEL : Cell Value, String Constant - LyNvIDOOHBIM len=0 
' 0018     23 LABEL : Cell Value, String Constant - PnnmPItQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - qEKQAUC len=0 
' 0018     23 LABEL : Cell Value, String Constant - TFWwtWEn len=0 
' 0018     26 LABEL : Cell Value, String Constant - TqfWBtXYGpb len=0 
' 0018     20 LABEL : Cell Value, String Constant - tVhOJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - vfADnJP len=0 
' 0018     21 LABEL : Cell Value, String Constant - vZlspY len=0 
' 0018     22 LABEL : Cell Value, String Constant - XArameI len=0 
' 0018     20 LABEL : Cell Value, String Constant - xczaO len=0 
' 0018     21 LABEL : Cell Value, String Constant - xkHrzE len=0 
' 0018     27 LABEL : Cell Value, String Constant - xLDjhrWzaLpX len=0 
' 0018     20 LABEL : Cell Value, String Constant - zxqyC len=0 
' 0018     21 LABEL : Cell Value, String Constant - zzCqsf 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 LABELSST : C
... (truncated)

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