Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 40753c08cf5b9ed1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:09 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: db826f6cf5d0eac015a246553dd32575 SHA-1: cbb552e5d0b5121958c271b4359534914680e605 SHA-256: 40753c08cf5b9ed11410b9220274109a81464f3ab882a1ebf8fc2adeb78d37a7
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, indicated by the presence of an 'Auto_Open' defined name. This macro functionality is often used to automatically execute malicious code when the workbook is opened. The critical heuristics suggest the macros are designed to run dangerous functions, likely for downloading and executing 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) 6449 bytes
SHA-256: 5ace4e8e22e2faa4ebb696ffe44b78b5c2a8fe7716890b8fa82ad921dc50e0f1
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 -  KEhYH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G140 
' 0018     20 LABEL : Cell Value, String Constant - DYiXL len=0 
' 0018     27 LABEL : Cell Value, String Constant - exPaWxzmYREY len=0 
' 0018     22 LABEL : Cell Value, String Constant - fholBhS len=0 
' 0018     20 LABEL : Cell Value, String Constant - fUfnL len=0 
' 0018     25 LABEL : Cell Value, String Constant - jGXYGXwQFL len=0 
' 0018     25 LABEL : Cell Value, String Constant - mFpeLBKeMe len=0 
' 0018     24 LABEL : Cell Value, String Constant - mjBWqajme len=0 
' 0018     22 LABEL : Cell Value, String Constant - NXcTgPk len=0 
' 0018     25 LABEL : Cell Value, String Constant - oKctPJxgNa len=0 
' 0018     22 LABEL : Cell Value, String Constant - pnRRcJr len=0 
' 0018     26 LABEL : Cell Value, String Constant - qZdyNtXVBDH len=0 
' 0018     22 LABEL : Cell Value, String Constant - rNmNoor len=0 
' 0018     26 LABEL : Cell Value, String Constant - rUwxpfaUFhs len=0 
' 0018     22 LABEL : Cell Value, String Constant - tkiQplY len=0 
' 0018     27 LABEL : Cell Value, String Constant - UNBcKpMzsdDD len=0 
' 0018     25 LABEL : Cell Value, String Constant - UOLsGZdOWA len=0 
' 0018     24 LABEL : Cell Value, String Constant - UzcXbyLbT len=0 
' 0018     24 LABEL : Cell Value, String Constant - XcAvSwOIP len=0 
' 0018     24 LABEL : Cell Value, String Constant - zBySAXBQi len=0 
' 0018     22 LABEL : Cell Value, String Constant - znItPdv 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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