Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 791c3b3f41d34164…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:43 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 7302733b7d17dddc7644a726a9afa58f SHA-1: ef05bf169da5027839e6bcd7560a46d4df1b8e50 SHA-256: 791c3b3f41d34164aa1cc5ecf3a083c928a72ba4184e4405e48e707bade77cd0
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet that contains an Auto_Open defined name, indicating it will execute automatically when the workbook is opened. Heuristics indicate the use of dangerous formula APIs within the macro, suggesting it's designed to execute arbitrary code. The primary purpose is 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) 6712 bytes
SHA-256: 918c262a14ad99f97f75dda5a591ad3cee02ceba0c48b46dbdd06601eaf738e4
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 -  PSBmAL
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D186 
' 0018     22 LABEL : Cell Value, String Constant - CugIfYH len=0 
' 0018     25 LABEL : Cell Value, String Constant - DuJssgdFRy len=0 
' 0018     27 LABEL : Cell Value, String Constant - ESceMieXGkif len=0 
' 0018     23 LABEL : Cell Value, String Constant - fyGQElbI len=0 
' 0018     23 LABEL : Cell Value, String Constant - gMLsDjsh len=0 
' 0018     21 LABEL : Cell Value, String Constant - igPnqN len=0 
' 0018     20 LABEL : Cell Value, String Constant - Metuh len=0 
' 0018     22 LABEL : Cell Value, String Constant - nNoxZKp len=0 
' 0018     23 LABEL : Cell Value, String Constant - pOLyGNzv len=0 
' 0018     26 LABEL : Cell Value, String Constant - prNdyvSBpao len=0 
' 0018     26 LABEL : Cell Value, String Constant - qNufcZKhGsW len=0 
' 0018     27 LABEL : Cell Value, String Constant - uikJkAqoIbec len=0 
' 0018     25 LABEL : Cell Value, String Constant - WqCTKITiVA len=0 
' 0018     25 LABEL : Cell Value, String Constant - WUWTTMeoIq len=0 
' 0018     27 LABEL : Cell Value, String Constant - xKApPtoIIYrC len=0 
' 0018     27 LABEL : Cell Value, String Constant - xnCqjRoInwgm len=0 
' 0018     24 LABEL : Cell Value, String Constant - yGnmGquma len=0 
' 0018     27 LABEL : Cell Value, String Constant - yLabmqfcnUlh len=0 
' 0018     20 LABEL : Cell Value, String Constant - yZqZX len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZJdtjJhHJD 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/
... (truncated)

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