Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 535dd78031d55f1a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:41 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: c6a480f20ae202641162f566820521a3 SHA-1: 5a5c804ad3860b8ffdc843627f752b3019e94651 SHA-256: 535dd78031d55f1a5627c662bf889cebba5c610fc9d03c42ae194b0be8e6cde4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel document containing Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristic firings. The presence of an Auto_Open defined name suggests that the macro will execute automatically when the workbook is opened. The dangerous formula APIs used in the macro indicate it is designed to perform malicious actions, such as downloading and executing a second-stage 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) 6622 bytes
SHA-256: 5c14a77eb4c4f3338669fec06a0d53e4c9a87fe0ddc713965eb5db7ddbc95d95
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  wZQUA
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F131 
' 0018     21 LABEL : Cell Value, String Constant - EgwKUZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - GhTethu len=0 
' 0018     27 LABEL : Cell Value, String Constant - gPsfTVQRLYIo len=0 
' 0018     26 LABEL : Cell Value, String Constant - HKIDiDbytcd len=0 
' 0018     21 LABEL : Cell Value, String Constant - KpQoqF len=0 
' 0018     22 LABEL : Cell Value, String Constant - lCBQEUJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - NUCJjmYM len=0 
' 0018     27 LABEL : Cell Value, String Constant - OAGisjFiJXGp len=0 
' 0018     23 LABEL : Cell Value, String Constant - OeeZvcpz len=0 
' 0018     26 LABEL : Cell Value, String Constant - oTqExqqdPyv len=0 
' 0018     23 LABEL : Cell Value, String Constant - qQRkhaOF len=0 
' 0018     23 LABEL : Cell Value, String Constant - qTgWiYqn len=0 
' 0018     21 LABEL : Cell Value, String Constant - sRrCZi len=0 
' 0018     24 LABEL : Cell Value, String Constant - tGWzOylqP len=0 
' 0018     21 LABEL : Cell Value, String Constant - tXqvPO len=0 
' 0018     24 LABEL : Cell Value, String Constant - uluBLDekx len=0 
' 0018     21 LABEL : Cell Value, String Constant - vAFoBK len=0 
' 0018     27 LABEL : Cell Value, String Constant - wKmHVTypeYDE len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZOMNYOB len=0 
' 0018     23 LABEL : Cell Value, String Constant - zxNwImEi 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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