Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ca98c9bf45fa0792…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:32:51 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 9f2dc4fcb1bd19ddf82645097042c915 SHA-1: 73f92233cce7bd9ad00ac11cf846946461b084ac SHA-256: ca98c9bf45fa07922e7d61d6b6a6d090496d4161f5414f2616f26670d2662141
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, specifically an Auto_Open macro. This indicates an attempt to automatically execute code when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is intended to download and execute a second-stage payload, a common technique for malware delivery.

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) 6651 bytes
SHA-256: e00452d36b2fda73229ed92160555dc8c5febb78bed111d12b7e67a8b8984f27
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TVxbUWlwpxA
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G151 
' 0018     26 LABEL : Cell Value, String Constant - eDXhVyCYCgW len=0 
' 0018     24 LABEL : Cell Value, String Constant - hMjJqDtwx len=0 
' 0018     25 LABEL : Cell Value, String Constant - hQfQCkydEj len=0 
' 0018     24 LABEL : Cell Value, String Constant - hRUfuSuxN len=0 
' 0018     24 LABEL : Cell Value, String Constant - ItnlBNSYR len=0 
' 0018     27 LABEL : Cell Value, String Constant - jWQvYjmIkZOw len=0 
' 0018     22 LABEL : Cell Value, String Constant - KtHuuIm len=0 
' 0018     27 LABEL : Cell Value, String Constant - KtPYqTrYycac len=0 
' 0018     21 LABEL : Cell Value, String Constant - lHRDfq len=0 
' 0018     27 LABEL : Cell Value, String Constant - MHCEnQhNMQwL len=0 
' 0018     22 LABEL : Cell Value, String Constant - mvJniJb len=0 
' 0018     23 LABEL : Cell Value, String Constant - nefuhXSj len=0 
' 0018     23 LABEL : Cell Value, String Constant - oqbXfHzy len=0 
' 0018     26 LABEL : Cell Value, String Constant - rANdicYAomZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - ROdPuiVtZoF len=0 
' 0018     20 LABEL : Cell Value, String Constant - ryYTv len=0 
' 0018     21 LABEL : Cell Value, String Constant - VgptWk len=0 
' 0018     22 LABEL : Cell Value, String Constant - VRqUKkw len=0 
' 0018     23 LABEL : Cell Value, String Constant - WGbXWIXM len=0 
' 0018     22 LABEL : Cell Value, String Constant - zOiEOrs 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

... (truncated)