Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 61e5c540cd1a231f…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:45:49 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 6c0f7758eae42ff3012db75e66bf92af SHA-1: fa4549785e761c5000102265abe2559d8b5b33cd SHA-256: 61e5c540cd1a231fe98c7fdd390e3a59288c042fcf70f28315c54afdc5d58a16
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 sheet that contains an Auto_Open defined name, indicating it will execute macros automatically upon opening. The critical heuristic 'XLM Auto_Open with dangerous formula APIs' further confirms the use of potentially malicious functions like RUN. This suggests the file is designed to execute a second-stage payload upon opening.

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) 6370 bytes
SHA-256: 90c9edd78968b4185cb7ef19c524f830852a3f4bbc90e286937f5ce2bc49f14d
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 -  mKs
' 0018     25 LABEL : Cell Value, String Constant - aUtNuRtrtl len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G154 
' 0018     26 LABEL : Cell Value, String Constant - EInUiAoXjVh len=0 
' 0018     22 LABEL : Cell Value, String Constant - eTvxvWI len=0 
' 0018     20 LABEL : Cell Value, String Constant - ETxht len=0 
' 0018     26 LABEL : Cell Value, String Constant - hKwVznCmvLE len=0 
' 0018     23 LABEL : Cell Value, String Constant - hMvfHTuq len=0 
' 0018     22 LABEL : Cell Value, String Constant - hpqhzYT len=0 
' 0018     24 LABEL : Cell Value, String Constant - IktZPENlM len=0 
' 0018     26 LABEL : Cell Value, String Constant - MBwtRgIKLNa len=0 
' 0018     25 LABEL : Cell Value, String Constant - mlcArmVjLB len=0 
' 0018     27 LABEL : Cell Value, String Constant - mPqaPosFWOuv len=0 
' 0018     21 LABEL : Cell Value, String Constant - nnhcTG len=0 
' 0018     26 LABEL : Cell Value, String Constant - NSvJWteoqtr len=0 
' 0018     22 LABEL : Cell Value, String Constant - OsIoRAN len=0 
' 0018     26 LABEL : Cell Value, String Constant - QakHiKbmALN len=0 
' 0018     20 LABEL : Cell Value, String Constant - tJWMj len=0 
' 0018     23 LABEL : Cell Value, String Constant - utWLzpzO len=0 
' 0018     20 LABEL : Cell Value, String Constant - VUYck len=0 
' 0018     21 LABEL : Cell Value, String Constant - vXZPzN len=0 
' 0018     25 LABEL : Cell Value, String Constant - YGjJkOFjnV 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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