Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4d2db8edc5b76d04…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:22 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: c1e597ef010312a9827641003d774c55 SHA-1: 31c41f5d0449083cc7c8f397e09e6ccf15158d66 SHA-256: 4d2db8edc5b76d0467ae119745ac2f8165e3680bf8ca9f65e69cfbb84b8fd35a
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 critical heuristic firing. This indicates the workbook is configured to automatically execute XLM macros upon opening. The presence of dangerous formula APIs like RUN suggests the macros are intended to execute arbitrary code, likely leading to the download and execution of 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) 6632 bytes
SHA-256: 15bc1988289dd30a41d31ce2b9d44a43e5f6212036dcc2af1f755b6b30551c00
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  CzbJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C163 
' 0018     24 LABEL : Cell Value, String Constant - azmZnbrME len=0 
' 0018     21 LABEL : Cell Value, String Constant - Caygeb len=0 
' 0018     25 LABEL : Cell Value, String Constant - COKjlMTWLm len=0 
' 0018     26 LABEL : Cell Value, String Constant - DGktrOZetON len=0 
' 0018     25 LABEL : Cell Value, String Constant - dJLHZrRbeI len=0 
' 0018     23 LABEL : Cell Value, String Constant - eCnNqzGD len=0 
' 0018     23 LABEL : Cell Value, String Constant - IkenzutZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - LNJnDPE len=0 
' 0018     22 LABEL : Cell Value, String Constant - MiKidCH len=0 
' 0018     20 LABEL : Cell Value, String Constant - mtOQR len=0 
' 0018     20 LABEL : Cell Value, String Constant - nTBCz len=0 
' 0018     24 LABEL : Cell Value, String Constant - oHgGVlLas len=0 
' 0018     27 LABEL : Cell Value, String Constant - pFPPPpLjztsP len=0 
' 0018     22 LABEL : Cell Value, String Constant - qEgHNbQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - qEICNkKueGZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - rhPxXb len=0 
' 0018     27 LABEL : Cell Value, String Constant - RjkeEpxoEwGf len=0 
' 0018     24 LABEL : Cell Value, String Constant - UdSWHUftp len=0 
' 0018     20 LABEL : Cell Value, String Constant - UyNxj len=0 
' 0018     24 LABEL : Cell Value, String Constant - ychXnOGLh 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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