Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4af970ffd49c19c3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:24:52 Authoring application: Microsoft Excel First seen: 2021-05-22
MD5: 33a2b39a574b38b1342b47e14d0f5b26 SHA-1: c31e19bd175dd751a97683b7ab122e8457db7fb3 SHA-256: 4af970ffd49c19c3f02cbe55d554f87e4f007057d74c5413cf670720c62710e1
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 presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely to download and run a second-stage payload. The specific function used, RUN, is a critical indicator of malicious intent.

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) 6454 bytes
SHA-256: cec10e563e6a623bf41d449b042948f42ee44cc0ac3939d5022c7c70974984bd
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  rMvpWp
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B159 
' 0018     24 LABEL : Cell Value, String Constant - AwtzYlRlR len=0 
' 0018     21 LABEL : Cell Value, String Constant - bFkWGm len=0 
' 0018     21 LABEL : Cell Value, String Constant - BpCaSH len=0 
' 0018     21 LABEL : Cell Value, String Constant - BtPfff len=0 
' 0018     26 LABEL : Cell Value, String Constant - EatwbqbhymK len=0 
' 0018     21 LABEL : Cell Value, String Constant - EWRmIs len=0 
' 0018     25 LABEL : Cell Value, String Constant - eXUCoUIQtL len=0 
' 0018     24 LABEL : Cell Value, String Constant - fcYaAfnbS len=0 
' 0018     23 LABEL : Cell Value, String Constant - FPKShsiU len=0 
' 0018     21 LABEL : Cell Value, String Constant - FzCXmd len=0 
' 0018     25 LABEL : Cell Value, String Constant - GblprxqCzi len=0 
' 0018     21 LABEL : Cell Value, String Constant - gqQhgS len=0 
' 0018     21 LABEL : Cell Value, String Constant - LZwaNW len=0 
' 0018     25 LABEL : Cell Value, String Constant - nfVWNrkDXu len=0 
' 0018     21 LABEL : Cell Value, String Constant - PgqxIs len=0 
' 0018     23 LABEL : Cell Value, String Constant - qiTDmKPp len=0 
' 0018     25 LABEL : Cell Value, String Constant - RoaQDFFjmj len=0 
' 0018     23 LABEL : Cell Value, String Constant - vXZDwXhK len=0 
' 0018     23 LABEL : Cell Value, String Constant - wQLIEtcY len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZQVwrlQz 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 LABELSST 
... (truncated)

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