Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 232775d29fb31e40…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:43 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 183d26e4ba91508b4b7b378885819fa2 SHA-1: 507499bd262c0e46a75e75d239b1341efe7b292b SHA-256: 232775d29fb31e40d730047e0a02dbbccda2d72f2fface2b87abb535af4c00d4
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 function. This function is designed to automatically execute when the workbook is opened, and the presence of dangerous formula APIs indicates it's intended to run malicious code. The macro sheet likely serves to download and execute a second-stage payload, a common technique for initial execution.

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) 6852 bytes
SHA-256: 2c64685566e7f4753793ad07c30761f9c66736f3808b702d976aa9b46b49ad3e
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 -  meAbRjoLMz
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E168 
' 0018     26 LABEL : Cell Value, String Constant - bTVjYtRQuGZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - cUayI len=0 
' 0018     23 LABEL : Cell Value, String Constant - ebABcAUg len=0 
' 0018     24 LABEL : Cell Value, String Constant - fslueQqUZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - gGuNZb len=0 
' 0018     24 LABEL : Cell Value, String Constant - hTeEfvDMZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - hXMtyfQS len=0 
' 0018     23 LABEL : Cell Value, String Constant - INjortaQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - kAZRjwgsZP len=0 
' 0018     24 LABEL : Cell Value, String Constant - kwOEouiXQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - Ngeju len=0 
' 0018     21 LABEL : Cell Value, String Constant - pLAWSb len=0 
' 0018     21 LABEL : Cell Value, String Constant - qjIXcW len=0 
' 0018     24 LABEL : Cell Value, String Constant - SSCscUytN len=0 
' 0018     22 LABEL : Cell Value, String Constant - vNXdrFn len=0 
' 0018     22 LABEL : Cell Value, String Constant - VuRQBun len=0 
' 0018     22 LABEL : Cell Value, String Constant - VXhFvYB len=0 
' 0018     25 LABEL : Cell Value, String Constant - wlZFLNKlmo len=0 
' 0018     21 LABEL : Cell Value, String Constant - YHCaTF len=0 
' 0018     24 LABEL : Cell Value, String Constant - YZWaTjDDW 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 LABELSS
... (truncated)

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