Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3f4361ba442bd8d8…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:14 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 78f982428ee4060c542563f10a4fa52d SHA-1: e0ad46eed8f49ffb63995e2b88a5b76abf924419 SHA-256: 3f4361ba442bd8d8c787ec9b1cf3795be33ada37b460fe05f86e0c966cc6cff2
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-enabled workbook containing an Auto_Open defined name, which is a critical indicator of malicious intent. This technique allows for the execution of arbitrary commands upon opening the workbook, commonly used to download and execute further malicious payloads. The presence of dangerous formula APIs like RUN further supports this conclusion.

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) 6647 bytes
SHA-256: 6a7cf652a9adde68fb251e2fa58f9eafc8ae130309c32a9c26db62cc75004576
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  NEHeWTvGtj
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I175 
' 0018     25 LABEL : Cell Value, String Constant - bfhAOHhQjr len=0 
' 0018     21 LABEL : Cell Value, String Constant - DixrzW len=0 
' 0018     25 LABEL : Cell Value, String Constant - ffVHMkLVBl len=0 
' 0018     21 LABEL : Cell Value, String Constant - GRWDcv len=0 
' 0018     27 LABEL : Cell Value, String Constant - GvOrSHTIdmfD len=0 
' 0018     23 LABEL : Cell Value, String Constant - IMFjqngs len=0 
' 0018     20 LABEL : Cell Value, String Constant - JHmty len=0 
' 0018     22 LABEL : Cell Value, String Constant - KyFXkFH len=0 
' 0018     22 LABEL : Cell Value, String Constant - LDMmlBT len=0 
' 0018     26 LABEL : Cell Value, String Constant - mqcTQzMVXUd len=0 
' 0018     24 LABEL : Cell Value, String Constant - PmaStVFOT len=0 
' 0018     26 LABEL : Cell Value, String Constant - QNxNRiUXOzn len=0 
' 0018     26 LABEL : Cell Value, String Constant - QTtmlTrFBzA len=0 
' 0018     25 LABEL : Cell Value, String Constant - SqApyDHueB len=0 
' 0018     22 LABEL : Cell Value, String Constant - SXtvBrx len=0 
' 0018     24 LABEL : Cell Value, String Constant - SXuyMQACm len=0 
' 0018     26 LABEL : Cell Value, String Constant - TKShAiupcFJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - XwGnQQwdAtVm len=0 
' 0018     25 LABEL : Cell Value, String Constant - YcWDoNXmzZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZZTDohMwazC 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 Constan
... (truncated)

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