Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1d137af6723e11ff…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:37:38 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: b017b5c061e4db122abb1907d122b286 SHA-1: 3bd96e01681d148f178ef2e39d2da7d8b5fc4a67 SHA-256: 1d137af6723e11ff567a174d89a5f234264950cffb188423669ec4cb5e9ebd7d
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open defined name, which is a common technique for executing malicious code upon opening the workbook. The macro sheet contains dangerous formula APIs, suggesting it is designed to perform actions beyond typical spreadsheet functions, such as downloading and executing a 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) 6551 bytes
SHA-256: 95d17b254bedb133ed6552919142bd1ee833cb97a4aaa51cb91be67eba76e3b4
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Dgg
' 0018     27 LABEL : Cell Value, String Constant - aiMhrtkiblfP len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E172 
' 0018     20 LABEL : Cell Value, String Constant - DnUef len=0 
' 0018     27 LABEL : Cell Value, String Constant - dVsplNCgAyeP len=0 
' 0018     22 LABEL : Cell Value, String Constant - efKxiQd len=0 
' 0018     22 LABEL : Cell Value, String Constant - fUqtWQI len=0 
' 0018     27 LABEL : Cell Value, String Constant - gSUIWktSwoUp len=0 
' 0018     26 LABEL : Cell Value, String Constant - GuCngIuURxZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - gzeVebYE len=0 
' 0018     22 LABEL : Cell Value, String Constant - IXdjWbr len=0 
' 0018     22 LABEL : Cell Value, String Constant - KPwamxN len=0 
' 0018     22 LABEL : Cell Value, String Constant - mPhqatz len=0 
' 0018     27 LABEL : Cell Value, String Constant - NdMDLlvWxHyI len=0 
' 0018     23 LABEL : Cell Value, String Constant - ndZQSrAn len=0 
' 0018     23 LABEL : Cell Value, String Constant - OuyoeykC len=0 
' 0018     24 LABEL : Cell Value, String Constant - powLSGHrt len=0 
' 0018     27 LABEL : Cell Value, String Constant - rHPTIKxyKgFk len=0 
' 0018     24 LABEL : Cell Value, String Constant - thiGrrgGV len=0 
' 0018     20 LABEL : Cell Value, String Constant - TlBoQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - wMjLH len=0 
' 0018     21 LABEL : Cell Value, String Constant - yAcnmX 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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