Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b79e5b04fd3ec5c9…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:33:52 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: b92fa73ccfdef9364507a877b5704580 SHA-1: 2eefc258945d4808bec0e9b458bca851a395d784 SHA-256: b79e5b04fd3ec5c9f2a288ce397b9fdf3ce92d55a3729f3e32cff6a5fd43464e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely downloading and running a second-stage payload. No specific family could be identified.

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) 6445 bytes
SHA-256: 10538f27e0dc77ca51670023f4fea3716bc939e0499f9fe67d047e73356f118e
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 -  jgBsj
' 0018     25 LABEL : Cell Value, String Constant - aPCiOrxDtI len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F170 
' 0018     25 LABEL : Cell Value, String Constant - bvrzkfAfvA len=0 
' 0018     22 LABEL : Cell Value, String Constant - fmeErCb len=0 
' 0018     22 LABEL : Cell Value, String Constant - jCHEjlv len=0 
' 0018     27 LABEL : Cell Value, String Constant - LPzOnUBlHnsx len=0 
' 0018     26 LABEL : Cell Value, String Constant - MYtZAQgurTG len=0 
' 0018     27 LABEL : Cell Value, String Constant - mZANEuwrXZQe len=0 
' 0018     22 LABEL : Cell Value, String Constant - NOQhewi len=0 
' 0018     26 LABEL : Cell Value, String Constant - NsqNbVbanFe len=0 
' 0018     26 LABEL : Cell Value, String Constant - nYbiqMYiuSw len=0 
' 0018     24 LABEL : Cell Value, String Constant - ORwUXOvTq len=0 
' 0018     20 LABEL : Cell Value, String Constant - QTaXk len=0 
' 0018     22 LABEL : Cell Value, String Constant - QVJQyze len=0 
' 0018     20 LABEL : Cell Value, String Constant - rjaQh len=0 
' 0018     20 LABEL : Cell Value, String Constant - rxRol len=0 
' 0018     24 LABEL : Cell Value, String Constant - UIZFufzmo len=0 
' 0018     21 LABEL : Cell Value, String Constant - VfjFtx len=0 
' 0018     23 LABEL : Cell Value, String Constant - xOSqrvhX len=0 
' 0018     20 LABEL : Cell Value, String Constant - YiVBc len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZmYzWtgtmc 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 
... (truncated)

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