Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 28fafb2b38b91fa0…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-25 10:40:17 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: a259e1e906fc761de6d6576da237f3bf SHA-1: b38f0d44fb5e1ece494020f9b12e33b2d79c6625 SHA-256: 28fafb2b38b91fa06cfda44ed00c0856803bca83b959de0268f2b62cab9286bc
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, which is a known method for executing malicious code. The macro sheet contains a reference to 'Auto_Open', suggesting it's designed to run automatically upon opening the workbook. The presence of dangerous formula APIs further supports malicious intent, likely 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) 6653 bytes
SHA-256: 2f8c90f39c98dbfae3f90c722e452bb76d7fbf0423bf7db41160a6ebc9c0ced1
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  payCIXCh
' 0018     20 LABEL : Cell Value, String Constant - AephN len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A185 
' 0018     23 LABEL : Cell Value, String Constant - bbXfWzTf len=0 
' 0018     22 LABEL : Cell Value, String Constant - DfMxcYJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - gcggPjx len=0 
' 0018     27 LABEL : Cell Value, String Constant - GsJHJAgGToux len=0 
' 0018     24 LABEL : Cell Value, String Constant - gwKdKbPie len=0 
' 0018     20 LABEL : Cell Value, String Constant - HkaxC len=0 
' 0018     21 LABEL : Cell Value, String Constant - JISmhu len=0 
' 0018     25 LABEL : Cell Value, String Constant - KBOcDnGeJA len=0 
' 0018     25 LABEL : Cell Value, String Constant - knIcUSShsM len=0 
' 0018     25 LABEL : Cell Value, String Constant - kVbdgnqgRC len=0 
' 0018     20 LABEL : Cell Value, String Constant - oMfFx len=0 
' 0018     24 LABEL : Cell Value, String Constant - PcDqpkbMV len=0 
' 0018     22 LABEL : Cell Value, String Constant - rBlZCQY len=0 
' 0018     23 LABEL : Cell Value, String Constant - RGQIYGuw len=0 
' 0018     26 LABEL : Cell Value, String Constant - rjCrGJQFLor len=0 
' 0018     26 LABEL : Cell Value, String Constant - shuZosbCgKl len=0 
' 0018     26 LABEL : Cell Value, String Constant - SvsXpWfAGuV len=0 
' 0018     21 LABEL : Cell Value, String Constant - tWruGY len=0 
' 0018     25 LABEL : Cell Value, String Constant - uogZlJljTu 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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