Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 764de1a102905c40…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:47:03 Authoring application: Microsoft Excel First seen: 2021-05-22
MD5: 84780ba6b0524c78f389c90b516027a4 SHA-1: e560b953541fed9306ab85e084bc87ae4313441a SHA-256: 764de1a102905c40085c9596b6bea32fc25c770ee086d7a051a2e42cd8c74398
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 automatically upon opening. Heuristics identified the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary code. This suggests the macro is designed to download and execute 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) 6442 bytes
SHA-256: 12bc5ebb2b27ece91964a0b20e12096d56f7f8c95b987bd534f612cff7ebcc50
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 -  hTOLi
' 0018     23 LABEL : Cell Value, String Constant - aLqnSkqC len=0 
' 0018     23 LABEL : Cell Value, String Constant - AMEiPOef len=0 
' 0018     20 LABEL : Cell Value, String Constant - aupQb len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B133 
' 0018     23 LABEL : Cell Value, String Constant - DgsjyLJe len=0 
' 0018     20 LABEL : Cell Value, String Constant - diCEN len=0 
' 0018     27 LABEL : Cell Value, String Constant - HPClPCKKjjvH len=0 
' 0018     25 LABEL : Cell Value, String Constant - IWLvvVNNTo len=0 
' 0018     25 LABEL : Cell Value, String Constant - kdhWXLoRrB len=0 
' 0018     20 LABEL : Cell Value, String Constant - maXZf len=0 
' 0018     24 LABEL : Cell Value, String Constant - mrclmeFYR len=0 
' 0018     26 LABEL : Cell Value, String Constant - NcCVuAmdOBw len=0 
' 0018     25 LABEL : Cell Value, String Constant - NyHikogKAJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - QzkntwSKf len=0 
' 0018     27 LABEL : Cell Value, String Constant - rmJyQiOpazkg len=0 
' 0018     27 LABEL : Cell Value, String Constant - TuRUEwrFFBZp len=0 
' 0018     26 LABEL : Cell Value, String Constant - VVeEShqOoAA len=0 
' 0018     21 LABEL : Cell Value, String Constant - wYdrkH len=0 
' 0018     25 LABEL : Cell Value, String Constant - xPEkTXlpbZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - YDMywEI len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZdPrg 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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