Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ec84a3eb6fce3237…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:40:10 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 0186cfff3ee4bc389da6494521302e52 SHA-1: 59ee809171c128f1ecc9780f6b5052ed6bd44414 SHA-256: ec84a3eb6fce323755ef1ed34aec85a610a554a7681c11f4326b216569633fe4
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 function, which is a known technique for executing malicious code upon opening the document. The critical heuristics indicate the presence of dangerous formula APIs within the XLM macro, suggesting it's designed to run arbitrary commands. No specific family could be identified, but the technique is common for initial execution.

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) 6387 bytes
SHA-256: 933a0fdddb2f0835d90f47e064f3d6f036e26fb71c604a6606ab6d17aba8967a
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  LGk
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C165 
' 0018     24 LABEL : Cell Value, String Constant - BKbZOXxxg len=0 
' 0018     27 LABEL : Cell Value, String Constant - CbHbxHuhJaaI len=0 
' 0018     25 LABEL : Cell Value, String Constant - dqnHNlytxT len=0 
' 0018     22 LABEL : Cell Value, String Constant - eIPKQQl len=0 
' 0018     25 LABEL : Cell Value, String Constant - FkoGuZbXGy len=0 
' 0018     23 LABEL : Cell Value, String Constant - hSDWjbHC len=0 
' 0018     26 LABEL : Cell Value, String Constant - ibNIsGAYCrB len=0 
' 0018     26 LABEL : Cell Value, String Constant - IBzHiCUKCWl len=0 
' 0018     21 LABEL : Cell Value, String Constant - iQsnhP len=0 
' 0018     22 LABEL : Cell Value, String Constant - IRQpnaf len=0 
' 0018     21 LABEL : Cell Value, String Constant - LcNjsC len=0 
' 0018     26 LABEL : Cell Value, String Constant - LqpbZDepaky len=0 
' 0018     24 LABEL : Cell Value, String Constant - QBPkpqBmI len=0 
' 0018     26 LABEL : Cell Value, String Constant - QGbqWsnsIor len=0 
' 0018     24 LABEL : Cell Value, String Constant - rbWBRwexb len=0 
' 0018     22 LABEL : Cell Value, String Constant - rQPQRIb len=0 
' 0018     23 LABEL : Cell Value, String Constant - scEVdfQB len=0 
' 0018     25 LABEL : Cell Value, String Constant - vIMthvReCZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - wYlYqAqSaA len=0 
' 0018     23 LABEL : Cell Value, String Constant - yoTYDkZD 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
' 0
... (truncated)

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