Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f712e88d2630343b…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:28 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: d7f7b37ae2a7ac9aba95b0487384b7c0 SHA-1: 9abc1f966a4fa7bab7509c9412dad0565a94b5e9 SHA-256: f712e88d2630343b506a22124307e8a1f3dbe76d739bf3c783d1458d8b6c39e6
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open defined name and dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute automatically and likely download or execute a secondary 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) 6498 bytes
SHA-256: bb6fa23527e2b9a0a5b1812ba99dd187844057244866b4c234fa825d2fb7c887
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  UsJUZF
' 0018     22 LABEL : Cell Value, String Constant - aiDjUIV len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F150 
' 0018     24 LABEL : Cell Value, String Constant - AVrUWCCPi len=0 
' 0018     23 LABEL : Cell Value, String Constant - BrlQhFYm len=0 
' 0018     21 LABEL : Cell Value, String Constant - bUjJeh len=0 
' 0018     22 LABEL : Cell Value, String Constant - CDVPDoL len=0 
' 0018     22 LABEL : Cell Value, String Constant - dgssHom len=0 
' 0018     23 LABEL : Cell Value, String Constant - ECMcOTNa len=0 
' 0018     26 LABEL : Cell Value, String Constant - FhGJRDJFzjN len=0 
' 0018     24 LABEL : Cell Value, String Constant - GJdWQZbPi len=0 
' 0018     24 LABEL : Cell Value, String Constant - jtnvdIXyS len=0 
' 0018     21 LABEL : Cell Value, String Constant - lcCgUl len=0 
' 0018     24 LABEL : Cell Value, String Constant - mABHlgkhS len=0 
' 0018     22 LABEL : Cell Value, String Constant - mEzXPrw len=0 
' 0018     23 LABEL : Cell Value, String Constant - nKhcpljb len=0 
' 0018     24 LABEL : Cell Value, String Constant - OhzEcgEgN len=0 
' 0018     22 LABEL : Cell Value, String Constant - pJKhBpe len=0 
' 0018     26 LABEL : Cell Value, String Constant - xiRzeiJmxyL len=0 
' 0018     21 LABEL : Cell Value, String Constant - xRNZXo len=0 
' 0018     22 LABEL : Cell Value, String Constant - XydcZSP len=0 
' 0018     21 LABEL : Cell Value, String Constant - zBlKDA 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 
... (truncated)

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