Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4c677928dc0a0df0…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:47:41 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: cef0c94e58ee788aec79addd16c2ef0d SHA-1: 8c426bac8a7c260bca991e5df7bb7b8a53b331d6 SHA-256: 4c677928dc0a0df0cb991ce3985403b1426f27b32a87ff6626b3b6f74ab240b9
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, which is a common technique for executing malicious code upon opening. The presence of dangerous formula APIs in the Auto_Open macro indicates an intent to run arbitrary commands. While the specific payload is not visible, the mechanism strongly suggests a downloader or initial execution stage.

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) 6866 bytes
SHA-256: 24b0367576817cee6942e974b3047617200e9d063f3fe83a68b8d2e2d337fc29
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  TsnzPRyjyQ
' 0018     23 LABEL : Cell Value, String Constant - ANshnvRw len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G173 
' 0018     23 LABEL : Cell Value, String Constant - bWylXCVf len=0 
' 0018     23 LABEL : Cell Value, String Constant - cdnpkaVJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - CXXBbdzm len=0 
' 0018     22 LABEL : Cell Value, String Constant - dKzUjXy len=0 
' 0018     26 LABEL : Cell Value, String Constant - eiHTJnTtBvC len=0 
' 0018     25 LABEL : Cell Value, String Constant - ektZBToFfY len=0 
' 0018     20 LABEL : Cell Value, String Constant - FAABF len=0 
' 0018     25 LABEL : Cell Value, String Constant - HhtTgebvvo len=0 
' 0018     21 LABEL : Cell Value, String Constant - IyxGwD len=0 
' 0018     23 LABEL : Cell Value, String Constant - NmJcOdtE len=0 
' 0018     23 LABEL : Cell Value, String Constant - NQXmtsPU len=0 
' 0018     22 LABEL : Cell Value, String Constant - OwETcUC len=0 
' 0018     25 LABEL : Cell Value, String Constant - PurNXGuVyh len=0 
' 0018     21 LABEL : Cell Value, String Constant - PUUwHC len=0 
' 0018     23 LABEL : Cell Value, String Constant - saRLYZkm len=0 
' 0018     27 LABEL : Cell Value, String Constant - TCFTdZNyjOoV len=0 
' 0018     23 LABEL : Cell Value, String Constant - UpuiAOwe len=0 
' 0018     22 LABEL : Cell Value, String Constant - vDdNSyJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - vKvTtTI 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 
... (truncated)

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