Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f6f7666166cba37d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:45 Authoring application: Microsoft Excel First seen: 2021-10-16
MD5: da9b41b7ea663449ce9b0437e97a07fa SHA-1: f409a19a788d68f38ac9b690c48fec53c329f0e8 SHA-256: f6f7666166cba37d63ebce17104ab71b866f3973343cdbe9255e07bd434dc8dd
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 finding. This indicates the macro sheet is designed to automatically execute code upon opening the workbook. The presence of dangerous formula APIs like RUN further confirms its malicious intent to execute arbitrary commands, likely leading to the download and execution of a secondary 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) 6383 bytes
SHA-256: 010d8d1e5e330ddcaab1210e8c3cf184a965f38738faabe85cdb67e929bc4648
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 -  cOw
' 0018     25 LABEL : Cell Value, String Constant - aFgVkRlAkx len=0 
' 0018     24 LABEL : Cell Value, String Constant - AtbYkXiLI len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B141 
' 0018     21 LABEL : Cell Value, String Constant - dDmbMO len=0 
' 0018     21 LABEL : Cell Value, String Constant - DJDTUp len=0 
' 0018     20 LABEL : Cell Value, String Constant - JBrue len=0 
' 0018     20 LABEL : Cell Value, String Constant - Jnnay len=0 
' 0018     24 LABEL : Cell Value, String Constant - KcQBnPAAw len=0 
' 0018     22 LABEL : Cell Value, String Constant - kpFHsdo len=0 
' 0018     27 LABEL : Cell Value, String Constant - lfOgMhHIWHwc len=0 
' 0018     26 LABEL : Cell Value, String Constant - lsbcEdsMSBt len=0 
' 0018     20 LABEL : Cell Value, String Constant - nwJtp len=0 
' 0018     27 LABEL : Cell Value, String Constant - oULHXPpZKBtl len=0 
' 0018     27 LABEL : Cell Value, String Constant - QIKEFWupxPrz len=0 
' 0018     25 LABEL : Cell Value, String Constant - RlpCLTuHHF len=0 
' 0018     26 LABEL : Cell Value, String Constant - sMxaRDtkhae len=0 
' 0018     25 LABEL : Cell Value, String Constant - TJnBMPxDXU len=0 
' 0018     24 LABEL : Cell Value, String Constant - upypyuszs len=0 
' 0018     25 LABEL : Cell Value, String Constant - wVCwZgQgXL len=0 
' 0018     26 LABEL : Cell Value, String Constant - YatndkVdFNP len=0 
' 0018     21 LABEL : Cell Value, String Constant - YqJmeA 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 
... (truncated)

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