Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 03fc41c90bbdc6b4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:36 Authoring application: Microsoft Excel First seen: 2021-09-17
MD5: 848168eeeaa56c166c2516374a53caad SHA-1: 91f48f300bcfca7188f334ac54c75a4929714f2a SHA-256: 03fc41c90bbdc6b41e7f87b5425bb0668b95bb4c0cafc44ba6a7052ae3bb215f
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The presence of dangerous formula APIs further increases the risk. While the exact payload is not discernible from the provided evidence, the Auto_Open function strongly suggests an attempt to immediately execute arbitrary commands or download further stages.

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) 6718 bytes
SHA-256: cb5c2fa5983f732fa5ff4f54152e56cfafbb2bef32e465ffdf4d97f3b2772a7b
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 -  hkKmyj
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E143 
' 0018     24 LABEL : Cell Value, String Constant - cmJqSzwcF len=0 
' 0018     20 LABEL : Cell Value, String Constant - CzOoR len=0 
' 0018     27 LABEL : Cell Value, String Constant - dJTlFJGPdhof len=0 
' 0018     25 LABEL : Cell Value, String Constant - EtXfnCURZm len=0 
' 0018     24 LABEL : Cell Value, String Constant - FSTDrbubs len=0 
' 0018     21 LABEL : Cell Value, String Constant - GeSzTl len=0 
' 0018     25 LABEL : Cell Value, String Constant - HjolndxJqI len=0 
' 0018     20 LABEL : Cell Value, String Constant - hpXOw len=0 
' 0018     27 LABEL : Cell Value, String Constant - jqhTGCDHvaeb len=0 
' 0018     22 LABEL : Cell Value, String Constant - neMmNGd len=0 
' 0018     24 LABEL : Cell Value, String Constant - qwwBTrGwB len=0 
' 0018     20 LABEL : Cell Value, String Constant - RDnyq len=0 
' 0018     24 LABEL : Cell Value, String Constant - ShiqABZSp len=0 
' 0018     20 LABEL : Cell Value, String Constant - sqAjQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - tzEQfd len=0 
' 0018     27 LABEL : Cell Value, String Constant - vpARMaooznqE len=0 
' 0018     25 LABEL : Cell Value, String Constant - XxlnwaOAmd len=0 
' 0018     23 LABEL : Cell Value, String Constant - yFniwomY len=0 
' 0018     25 LABEL : Cell Value, String Constant - YPpauRbzKf len=0 
' 0018     21 LABEL : Cell Value, String Constant - zXBaZq 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 L
... (truncated)

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