Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 decd282b7a088b6d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:46 Authoring application: Microsoft Excel First seen: 2021-11-03
MD5: 1db8f7c6b3b13cea3d7d88da7919a34c SHA-1: 19d5a0257bf381f915619a3ec9503c5cfb4b5636 SHA-256: decd282b7a088b6d54f328ac36ed7c27e5f811236a3b7e1dbc2e5d0348833e77
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a reference to a dangerous formula API, suggesting it's designed to download and execute a secondary 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) 6601 bytes
SHA-256: e3a73f485572c5aadf726c72ea25f4c3cb1f08b65b2967491ac9dd2b1fc1b949
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 -  DNbR
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I190 
' 0018     26 LABEL : Cell Value, String Constant - aWsJwIBOdhd len=0 
' 0018     23 LABEL : Cell Value, String Constant - aZMYXvcA len=0 
' 0018     26 LABEL : Cell Value, String Constant - cULXAvyjKbd len=0 
' 0018     21 LABEL : Cell Value, String Constant - EMGwHJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - Fiexioy len=0 
' 0018     27 LABEL : Cell Value, String Constant - hhdcTZZmfMSt len=0 
' 0018     25 LABEL : Cell Value, String Constant - LKxYyLVHMQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - MoBAXe len=0 
' 0018     23 LABEL : Cell Value, String Constant - NvlXIcFk len=0 
' 0018     27 LABEL : Cell Value, String Constant - RNEtGFhgKqiS len=0 
' 0018     22 LABEL : Cell Value, String Constant - RpAniLh len=0 
' 0018     24 LABEL : Cell Value, String Constant - SQZZASWqd len=0 
' 0018     25 LABEL : Cell Value, String Constant - TbrWlnaPZe len=0 
' 0018     21 LABEL : Cell Value, String Constant - vlXiZH len=0 
' 0018     24 LABEL : Cell Value, String Constant - WtNJdlqTC len=0 
' 0018     20 LABEL : Cell Value, String Constant - wWulT len=0 
' 0018     21 LABEL : Cell Value, String Constant - xDOALX len=0 
' 0018     27 LABEL : Cell Value, String Constant - xJHuhEAJxmXn len=0 
' 0018     22 LABEL : Cell Value, String Constant - yfQSnLI len=0 
' 0018     25 LABEL : Cell Value, String Constant - yWdGJklain 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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