Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b12ef043ce591f7e…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:32:20 Authoring application: Microsoft Excel First seen: 2021-10-12
MD5: 2757d7004f6803af135f82fc84db4279 SHA-1: e29e711cd87c7b57613cb0bb6c3d461668c74f35 SHA-256: b12ef043ce591f7e842dccd7aa9309588da52884c660929c504a7c6a58db726f
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 containing an Auto_Open defined name, which is a critical indicator of malicious intent. This technique allows for the automatic execution of embedded XLM macros when the workbook is opened, likely to download and execute a second-stage payload. The presence of dangerous formula APIs further supports this assessment.

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) 6373 bytes
SHA-256: cd70f1731680ec58df33f5e34c014138ee2cdf7c83fa53e43b311fa6fd08f011
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 -  oBaw
' 0018     25 LABEL : Cell Value, String Constant - adXBhLKiMO len=0 
' 0018     21 LABEL : Cell Value, String Constant - aukliX len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I159 
' 0018     25 LABEL : Cell Value, String Constant - EcJZRBXUnd len=0 
' 0018     25 LABEL : Cell Value, String Constant - eqaAbdUSvY len=0 
' 0018     24 LABEL : Cell Value, String Constant - EZPyobBSC len=0 
' 0018     24 LABEL : Cell Value, String Constant - hrYFWKBzz len=0 
' 0018     23 LABEL : Cell Value, String Constant - hYfawNdU len=0 
' 0018     26 LABEL : Cell Value, String Constant - jgHMSKabbAG len=0 
' 0018     25 LABEL : Cell Value, String Constant - MNxVGLgKcV len=0 
' 0018     22 LABEL : Cell Value, String Constant - nslfUqI len=0 
' 0018     23 LABEL : Cell Value, String Constant - OBQsTBDM len=0 
' 0018     22 LABEL : Cell Value, String Constant - oITurTY len=0 
' 0018     22 LABEL : Cell Value, String Constant - oKRIXrJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - pINCJyn len=0 
' 0018     23 LABEL : Cell Value, String Constant - SaYZRzMW len=0 
' 0018     20 LABEL : Cell Value, String Constant - szSpb len=0 
' 0018     23 LABEL : Cell Value, String Constant - TnXxXSLJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - UbRAQDUkikky len=0 
' 0018     21 LABEL : Cell Value, String Constant - xMXsuJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - YUCtvx 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 LABE
... (truncated)

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