Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6844047b3c1aee2e…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:41:55 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 3639db03bf2252937539030d4cacb568 SHA-1: c53cf66ab889772e2c5a40b2f45be6410624e122 SHA-256: 6844047b3c1aee2edf29b457485009a264a864a859fd3eccd8c99e3d13ead1b9
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an 'Auto_Open' defined name, which is a known mechanism for automatic execution of malicious code when the workbook is opened. The macro sheet itself contains references to dangerous functions, including 'RUN', suggesting it is intended to execute arbitrary code, likely 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) 6433 bytes
SHA-256: f6eb7bd732661d578807b451851d99769deae4c9a6c5f4a0fdb8c1075ae81b2f
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Paupsg
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F140 
' 0018     25 LABEL : Cell Value, String Constant - BTUVQSyqgv len=0 
' 0018     22 LABEL : Cell Value, String Constant - bUBXvUw len=0 
' 0018     26 LABEL : Cell Value, String Constant - ezhrLRLomxU len=0 
' 0018     24 LABEL : Cell Value, String Constant - GaOpFwxyc len=0 
' 0018     26 LABEL : Cell Value, String Constant - IZqMESRQzVr len=0 
' 0018     21 LABEL : Cell Value, String Constant - jHYRVF len=0 
' 0018     27 LABEL : Cell Value, String Constant - kerYJTbTsdHi len=0 
' 0018     22 LABEL : Cell Value, String Constant - LaZwoRE len=0 
' 0018     21 LABEL : Cell Value, String Constant - PEboxw len=0 
' 0018     21 LABEL : Cell Value, String Constant - qaSlZE len=0 
' 0018     22 LABEL : Cell Value, String Constant - rJfUpZA len=0 
' 0018     24 LABEL : Cell Value, String Constant - SeTcXOWqm len=0 
' 0018     20 LABEL : Cell Value, String Constant - TiOHm len=0 
' 0018     21 LABEL : Cell Value, String Constant - WVgVzi len=0 
' 0018     21 LABEL : Cell Value, String Constant - xblksh len=0 
' 0018     25 LABEL : Cell Value, String Constant - XIvuHFUFPI len=0 
' 0018     25 LABEL : Cell Value, String Constant - XmpgHcdgzT len=0 
' 0018     23 LABEL : Cell Value, String Constant - YgfPjXhI len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZRJsM len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZvUkgfzm 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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