Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2695111f6dca7453…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:47 Authoring application: Microsoft Excel First seen: 2021-09-22
MD5: da86511dd66ee9fefd6d72ffbece7235 SHA-1: e0ba24b6b94f864c960c0f3f5243989f798989ba SHA-256: 2695111f6dca745312ddfb5272e5f91ac7f4c0bbd6893197d45deb450341f59d
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known technique for executing malicious code. The macro sheet contains a reference to Auto_Open, suggesting it's designed to run automatically when the workbook is opened. This functionality is commonly abused to download and execute further stages of malware.

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) 6767 bytes
SHA-256: f18d2a262a4dc5a4b98af94892b95b6f513040b1738f7f0c75ad87306b1b1c09
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 -  zXKzKXyh
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H169 
' 0018     26 LABEL : Cell Value, String Constant - bcXtffvwcyO len=0 
' 0018     24 LABEL : Cell Value, String Constant - BiSrbLXSk len=0 
' 0018     22 LABEL : Cell Value, String Constant - DIUCLJK len=0 
' 0018     27 LABEL : Cell Value, String Constant - DnJKYPaFoyBa len=0 
' 0018     25 LABEL : Cell Value, String Constant - EPpURWfxYF len=0 
' 0018     25 LABEL : Cell Value, String Constant - EsTLKdBNII len=0 
' 0018     27 LABEL : Cell Value, String Constant - fQnmYFgqWngh len=0 
' 0018     23 LABEL : Cell Value, String Constant - gKZjqHCA len=0 
' 0018     21 LABEL : Cell Value, String Constant - HEyIUS len=0 
' 0018     26 LABEL : Cell Value, String Constant - hTShTbRsuMX len=0 
' 0018     25 LABEL : Cell Value, String Constant - HwfupptbLD len=0 
' 0018     21 LABEL : Cell Value, String Constant - ILLmWU len=0 
' 0018     21 LABEL : Cell Value, String Constant - jKfkfE len=0 
' 0018     21 LABEL : Cell Value, String Constant - PCHiPV len=0 
' 0018     21 LABEL : Cell Value, String Constant - rYxgbG len=0 
' 0018     23 LABEL : Cell Value, String Constant - sCwVnuNM len=0 
' 0018     23 LABEL : Cell Value, String Constant - tmoGIOVi len=0 
' 0018     26 LABEL : Cell Value, String Constant - uASBmiPZeTS len=0 
' 0018     25 LABEL : Cell Value, String Constant - wUiyvzFWou len=0 
' 0018     23 LABEL : Cell Value, String Constant - ytlNxLQm 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
' 0
... (truncated)

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