Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 edb22d4373e7d52c…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:44:33 Authoring application: Microsoft Excel First seen: 2021-09-22
MD5: 60d77a327484fd4bc0c6adebd1f3b215 SHA-1: 882a30c503ecf64b3a7dbb6bfebfaecb72ddf52e SHA-256: edb22d4373e7d52c05ecb0faf2056a4f9eaba1109cfc91372499497d1ae6ce42
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 defined name, which is a common technique for executing malicious code upon opening the document. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to download and execute a secondary payload. The presence of the sheet name 'YCxAb' is noted as a potential indicator.

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) 6527 bytes
SHA-256: 54a1f1d74091865a71636eabe528987eb509744a5eee5ee90e845c8287e3a367
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  YCxAb
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D185 
' 0018     22 LABEL : Cell Value, String Constant - DWgdzom len=0 
' 0018     22 LABEL : Cell Value, String Constant - evIowgW len=0 
' 0018     23 LABEL : Cell Value, String Constant - eVuZbCDB len=0 
' 0018     26 LABEL : Cell Value, String Constant - FAZZPhZsGbJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - GaBTP len=0 
' 0018     20 LABEL : Cell Value, String Constant - Hppnc len=0 
' 0018     22 LABEL : Cell Value, String Constant - iAWREfp len=0 
' 0018     22 LABEL : Cell Value, String Constant - KKqqUKK len=0 
' 0018     25 LABEL : Cell Value, String Constant - Mpgrlphffx len=0 
' 0018     20 LABEL : Cell Value, String Constant - mzFRX len=0 
' 0018     23 LABEL : Cell Value, String Constant - nDybTrYT len=0 
' 0018     21 LABEL : Cell Value, String Constant - PdJSNJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - PuRSMAxvv len=0 
' 0018     24 LABEL : Cell Value, String Constant - rpLdELwOF len=0 
' 0018     25 LABEL : Cell Value, String Constant - SyHQPXuUFD len=0 
' 0018     24 LABEL : Cell Value, String Constant - tyvCSMecM len=0 
' 0018     24 LABEL : Cell Value, String Constant - yBqtnGmEN len=0 
' 0018     20 LABEL : Cell Value, String Constant - yGYJG len=0 
' 0018     27 LABEL : Cell Value, String Constant - yJDHSZuJXrkD len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZNDVZearFTS 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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