Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c9e9226385e33e43…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:45:14 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: 445d6ef8da41ab6015c4afbbba133d44 SHA-1: fd4344161693112220cc6e5508c06f1919f3264c SHA-256: c9e9226385e33e43376e3f58798405c20569cef903f336b70777fc578317fd9e
140 Risk Score

Malware Insights

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

This Excel file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The presence of dangerous formula APIs like RUN indicates the macro is designed to execute arbitrary commands. The macro sheet likely serves to download and execute a second-stage payload, although the specific commands are truncated.

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) 6627 bytes
SHA-256: db45616469be4e8423295abbfaf3e3e94e8c5bd80bc481373c72fa05b33f9b5c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  RFzm
' 0018     26 LABEL : Cell Value, String Constant - AMqjUovsGyG len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F189 
' 0018     22 LABEL : Cell Value, String Constant - aYLNKXX len=0 
' 0018     27 LABEL : Cell Value, String Constant - CmojtAPQRZuQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - ewhRkpXH len=0 
' 0018     27 LABEL : Cell Value, String Constant - giAMzGipZXpS len=0 
' 0018     27 LABEL : Cell Value, String Constant - gZwStUfnmCwD len=0 
' 0018     24 LABEL : Cell Value, String Constant - iTdfvmYSl len=0 
' 0018     24 LABEL : Cell Value, String Constant - KzqrtwxwB len=0 
' 0018     26 LABEL : Cell Value, String Constant - LeLAzCnOsZk len=0 
' 0018     24 LABEL : Cell Value, String Constant - lzXgTzvkT len=0 
' 0018     21 LABEL : Cell Value, String Constant - MOGxHg len=0 
' 0018     26 LABEL : Cell Value, String Constant - QhkTCpgbQOS len=0 
' 0018     20 LABEL : Cell Value, String Constant - rDxfu len=0 
' 0018     21 LABEL : Cell Value, String Constant - sriQzt len=0 
' 0018     22 LABEL : Cell Value, String Constant - ucfACZP len=0 
' 0018     24 LABEL : Cell Value, String Constant - UrEzkytYt len=0 
' 0018     27 LABEL : Cell Value, String Constant - wehHMCHzvhgj len=0 
' 0018     23 LABEL : Cell Value, String Constant - WKPDiygk len=0 
' 0018     26 LABEL : Cell Value, String Constant - xkiUzAOyxcF len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZyuWFChz 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
... (truncated)

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