Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 41f15bffbaa246dd…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:46:14 Authoring application: Microsoft Excel First seen: 2021-06-17
MD5: c09e65f0b5eea5bff0ea76e0ac5cafc6 SHA-1: 694875604aa26d1a75693bde468d7d674dd8e72a SHA-256: 41f15bffbaa246ddd73a89e4a65a2596919fcd4a2f86a8253b04c677de2fb44d
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 automatically when the workbook is opened, and the heuristics indicate it uses dangerous formula APIs, specifically 'RUN'. This strongly suggests the macro is intended to download and execute a secondary payload, a common technique for initial access and further compromise.

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) 6599 bytes
SHA-256: 8196a2f669c546531d7df4201332fc2f1664b2b91d1a5ee36d74c9a488c007e9
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cql
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F184 
' 0018     22 LABEL : Cell Value, String Constant - AYSJKXM len=0 
' 0018     25 LABEL : Cell Value, String Constant - BhGTHHAwLH len=0 
' 0018     21 LABEL : Cell Value, String Constant - bPZpxp len=0 
' 0018     24 LABEL : Cell Value, String Constant - CJxBMdwqk len=0 
' 0018     21 LABEL : Cell Value, String Constant - dQAyah len=0 
' 0018     21 LABEL : Cell Value, String Constant - IUzOvT len=0 
' 0018     27 LABEL : Cell Value, String Constant - jcAJgkRaqPFL len=0 
' 0018     22 LABEL : Cell Value, String Constant - KJtxwJA len=0 
' 0018     20 LABEL : Cell Value, String Constant - lyzlG len=0 
' 0018     22 LABEL : Cell Value, String Constant - MPuFvvD len=0 
' 0018     22 LABEL : Cell Value, String Constant - rkiyPBW len=0 
' 0018     21 LABEL : Cell Value, String Constant - RXtgmr len=0 
' 0018     25 LABEL : Cell Value, String Constant - svmDPbOuJW len=0 
' 0018     21 LABEL : Cell Value, String Constant - taozXt len=0 
' 0018     27 LABEL : Cell Value, String Constant - tDyewqmeuloV len=0 
' 0018     26 LABEL : Cell Value, String Constant - wOkaKITApMr len=0 
' 0018     27 LABEL : Cell Value, String Constant - XOhsVoYNLJLI len=0 
' 0018     22 LABEL : Cell Value, String Constant - zHsszmL len=0 
' 0018     27 LABEL : Cell Value, String Constant - zMasALgmLJlg len=0 
' 0018     24 LABEL : Cell Value, String Constant - zwZcWbCOW 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 LA
... (truncated)

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