Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6941f2941374ef62…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:55 Authoring application: Microsoft Excel First seen: 2021-09-15
MD5: ec20b3eb912e926581a56450766a45ff SHA-1: eca403eefd1425a91036d041d847a302bddb71fc SHA-256: 6941f2941374ef62ffad2d3ac8fd91a17cb2129a9c63c3d15e36ead42d9c0812
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 containing an Auto_Open function. This function is designed to execute arbitrary commands, indicated by the critical heuristic firing for dangerous formula APIs like RUN. The macro sheet itself contains obfuscated data, suggesting an attempt to hide malicious code. The primary purpose is 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) 6497 bytes
SHA-256: ca7b1df141b966a702ae7f77f3b0998e0ee3e90c0e91054ed0fb10cc36adf9a1
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  XjvzkxOH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C146 
' 0018     23 LABEL : Cell Value, String Constant - bBgspUqg len=0 
' 0018     26 LABEL : Cell Value, String Constant - bfvQBQpZQEh len=0 
' 0018     20 LABEL : Cell Value, String Constant - CEJhm len=0 
' 0018     22 LABEL : Cell Value, String Constant - DfXXgJL len=0 
' 0018     24 LABEL : Cell Value, String Constant - djnOViDfJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - DpmgAQQrKoJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - eUbUzX len=0 
' 0018     26 LABEL : Cell Value, String Constant - iXPKPimVJuP len=0 
' 0018     22 LABEL : Cell Value, String Constant - kvxoRyb len=0 
' 0018     21 LABEL : Cell Value, String Constant - PzVqlN len=0 
' 0018     25 LABEL : Cell Value, String Constant - sXFCrCiQyl len=0 
' 0018     20 LABEL : Cell Value, String Constant - UekBB len=0 
' 0018     22 LABEL : Cell Value, String Constant - UGHVPor len=0 
' 0018     22 LABEL : Cell Value, String Constant - uMyHSTc len=0 
' 0018     22 LABEL : Cell Value, String Constant - wgVAKwt len=0 
' 0018     20 LABEL : Cell Value, String Constant - wKpPC len=0 
' 0018     23 LABEL : Cell Value, String Constant - xQaTCgYn len=0 
' 0018     25 LABEL : Cell Value, String Constant - XwwLKkpNaA len=0 
' 0018     20 LABEL : Cell Value, String Constant - yykAh len=0 
' 0018     27 LABEL : Cell Value, String Constant - zPNuJRnAhkft 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 LABELSS
... (truncated)

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